LIBRARY OF CONGRESS. 



Chap._^-„. Copyright No._ 



SheitZM/.:; 



UNITED STATES OF AMERICA. 



ESSENTIALS 



OF 



MEDICAL AND CLINICAL 
CHEMISTRY. 

WITH LABORATORY EXERCISES. 



BY 
SAMUEL E. WOODY, A.M., M.D. 



FOURTH EDITION REVISED AND ENLARGED. 



ILLUSTRATED. 



PHILADELPHIA : 

P. BLAKISTON'S SON & CO., 

1012 Walnut Street, 

1900. 



*> 



028 



TWO copita H^c&ivfio, 
Library 0/ Congret* 
Office of th* 

JUN8-19G0 

Itffllttr of Copyright* 
SECOND COPY. 



62525 



Copyright, 1900, by P. Blakiston's Son & Co. 






Press of 

"VVickeisham P. in ting Co., 

Lancaster, Pa. 



PREFACE TO FOURTH EDITION. 



In this Fourth Edition the text has been largely re-written, 
especially the clinical portion, and much new matter added. 
Realizing the need of a brief text-book that would also serve as a 
practical laboratory guide, the author has, wherever the directions 
in the text are not sufficiently explicit, added, as foot-notes, a 
series of simple laboratory exercises embodying such experiments 
as he has had his students perform during his twenty years of med- 
ical laboratory teaching. It will be noticed that the experiments are 
so simple as to require only such apparatus as the general practi- 
tioner has, or should have, about his office. In keeping with the 
present pharmacopoeia, the old spelling is retained. 

Thanks for valuable assistance is extended to the author's col- 
leagues, Drs. Solomon, Rominger and Rapp, Professors of Materia 
Medica, Inorganic Chemistry, and Organic and Clinical Chem- 
istry, respectively, in the Medical Department of Kentucky 
University ; to Dr. Harris M. Kelty, Professor of Chemistry in 
the Louisville Medical College, and to Dr. fas. Lewis Howe, 
Professor of Chemistry in Washington and Lee University. 

This edition is presented with the hope that it may meet as 
cordial a reception as its predecessors, and that teacher and 
student will find the author's labor has lightened theirs. 

600 West Broadway, Louisville, June, igoo. 

(in) 



TABLE OF CONTENTS. 



PAGE 

INTRODUCTION 9-17 

Definition of chemistry, 9; properties of matter, 11 ; specific gravity, 
10; states of matter, 14; table of elements and atomic weights, 
15; atomic theory, 16; symbols, formulae, equations, 17. 

PART I.— INORGANIC CHEMISTRY 18-132 

Classification of the Elements 19 

I. Preliminary Group • I 9~3 I 

Hydrogen, 19; oxygen, 21; ozone, 23; water, 25; natural 
waters, 27; purification of water, 29; hydrogen dioxide, 
30; ("Radicals, 31 : affinities, 32; valences, 34; nomen- 
clature, 36.) 

II. Chlorine Group 37~44 

Fluorine, Chlorine, Bromine, Iodine, 37. (Nomenclature 
of acids and salts, 40.) Hydracids of chlorine group, 41 ; 
oxysalts of chlorine group, 43. 

III. Sulphur Group 44~5 1 

Oxygen, 21; Sulphur, 45 : hydrogen sulphide, 46; carbon 
disulphide, 48; sulphur dioxide, sulphur trioxide, 49; 
sulphuric acid, 50; Selenium, Tellurium, 44. 

IV. Nitrogen Group 5 2_ 7 2 

Nitrogen, 52: the atmosphere, 53: (Argon, Helium, Kryp- 
ton, Neon, 55); ammonia, 55; nitrogen monoxide, di- 
oxide, trioxide, 58; tetroxide, pentoxide, 59. Phosphorus, 
60: hydride, 61; oxides and oxacids, 62. Arsenic, 63: 
arsine, 64; arsenous iodide, sulphide, oxide, 64; arsenic 
oxide, 65; toxicology of arsenic, 65. Antimony, 69: 
stibine, 69; oxide, sulphide, 70; tartar emetic, 70; toxi- 
cology of antimony, 70. Bismuth, 71 : nitrate, subnitrate, 
subcarbonate, 71. 

V. Carbon Group 72-86 

Carbon, 73: monoxide, 74; dioxide, 75; ventilation, 78; 
cyanogen, 79; cyanides, 80. Silicon, 81 : oxide, 81; 
silicates, 81; (The Metals, 81). Tin, 82. Lead, 82: 
oxides, nitrate, acetate, 83; chloride, sulphate, carbonate, 
84; sulphide, iodide, chromate, toxicology of, 85. 

(v) 



VI CONTENTS. 

PAGE 

VI. Potassium Group 86-97 

Hydrogen, 19; Lithium, 86; Ammonium, 87; hydrate,87; 
sulphide, carbonate, etc., 88. Sodium, 89 : chloride, 
89; dioxide, bicarbonate, etc., 90. Potassium: carbon- 
ate, acid salts, 91; bicarbonate, bitartrate, hydrate, 92; 
iodide, bromide, nitrate. 93; hypochlorite, 94; tests, 96. 
Caesium, Rubidium, 96. ( Acidimetry and Ukalimetry, 96.) 

VII. Calcium Group 97-102 

Calcium, 98: chloride, carbonate, oxide, 98; hydrate, hypo- 
chlorite, sulphate, phosphate, oxalate, 99; carbide, hard- 
waters, 100. Strontium, ici. Barium, 10 1. 

VIII. Magnesium Group 102-106 

Magnesium, 102: sulphate, 102; citrate, carbonate, oxide, 
hydrate, phosphates, 103. Zinc, 104: sulphate, chloride, 
104; carbonate, oxide, sulphide, 105. Cadmium, 106. 

IX. Aluminum Group 106-109 

Boron, 106: boric acid, borax, 107. Aluminum, 107: 
oxide, hydrate, chloride, sulphate, alum, ic8; silicates, 
109. Cerium, 109. Scandium, Gallium, Yttrium, Indium, 
Lanthanum, Neodymium, Praseodymium, Samarium, Er- 
bium, Ytterbium, Thallium, 106. 

X. Iron Group 1 10-1 18 

Chromium, no: oxides, chromates, no; bichromates, in. 
Manganese, ill: dioxide, sulphate, ill; sulphide, man- 
ganates, permanganates, 112. Iron, 112: reduced, 113; 
chlorides, sulphates, 114; hydrates, 115; nitrate, iodide, 
carbonate, sulphide, scale preparations, 116. Cobalt, 
Nickel, Molybdemum, Tungsten, Uranium, 117. 

XL Copper Group ... 1 18-129 

Copper, 118: sulphate, hydrates, 119; oxides, subacetate, 
120. Mercury, 121 : iodides, nitrates, sulphates, 122; 
chlorides, 123; oxides, oleate, sulphides, tests, 124. Silver, 
126: nitrate, oxide, 126; cyanide, chloride, bromide, 
iodide, 127. Gold, 128. (Platinum, etc., 129.) 
Analytical Tables: metallic radicals, 130; acidulous radicals, 131 ; 
solubilities, 132. 

PART II.— ORGANIC CHEMISTRY *33-i79 

General Considerations: definition, 133; peculiarities of carbon com- 
pounds, 133; homologous and isologous series, 134; ultimate 
analysis, 135; molecular formulae, =36. 



CONTENTS. Vll 

PAGE 

Hydrocarbons 1 37-144 

Table of classification, 137. 

Methane Series, 138, 139: petroleum, 138; methane, ethane, 139. 

Methane Series, 139: ethene, 139. 

Ethine Series, 139: acetylene, 139. 

Tritone Series, 140 : volatile oils, resins, 140; camphors, caout- 
chouc, gutta-percha, 141. 

Benzene Series: 141 : benzene, toluene, naphthalene, 142. 

Halogen Derivatives, 142: chloroform, 142; bromoform, 143; 
iodoform, 144. 
Alcuhols and their Derivatives 144-163 

Methyl Series, 144: table, 144. Alcohols: methyl alcohol, 145; 
ethyl alcohol. 146; amyl alcohol, sulphur alcohols, 148. Ethers, 
149: definitions, ethyl ether, 149, ethyl chloride, 150: ethyl 
bromide, ethyl nitrite, pentyl nitrite, 151. Aldehydes, 151 : 
methyl aldehyde, ethyl aldehyde, chloral, 152. Organic Acids, 
153: formic, acetic, 153; butyric, valerianic, 154; palmitic, 
stearic, oleic, 155. Table of homologous series of fat acids, 156. 

Methene Series, 157: oxalic acid, 157; lactic acid, succinic acid, 
malic acid, tartaiic acid, citric acid, 158. 

Methenyl Series, 158: glycerine, 159; nitroglycerine, 159. 

Benzene Series, 159: Phenol, 159; resorcin, creasote, guaiacol, 
160; cresol, salol, salophen, saccharin, 161. Aromatic Acids: 
benzoic, picric, 161; salicylic, gallic, pyrogallic, 162. 
Carbohydrates 163-168 

Amyloses, 163: cellulose, 163; gums, starch, 164; dextrin, gly- 
cogen, 165. 

Saccharoses, 166: cane sugar, milk sugar, 166; maltose, 167. 

Glucoses, 167: glucose, 167; Isevulose, 168. 
Glucosides 1 68, 1 69 

Amygdalin, salkin, 168; tannin, myronic acid, indican, etc., 169. 
Ammonia Substitution Compounds 169-172 

" -Amines " and "-amides," aniline, 170; trimethylamine, acetan- 
ilide, phenacetine, antipyrine, 171. 
Proteids 1 72-1 75 

Natural albumins, globulins, 173; derived albumins, 174; fibrins, 
peptones, albumoses, coagulated proteids, lardacein, 175. 
Alkaloids 1 75-1 79 

Natural alkaloids, 175; ptomaines, 176; leucomaines, bacterial 
proleids, antitoxme, 178; table of alkaloids, 179. 



Vlll CONTENTS. 

PAGE 

PART III.— CLINICAL CHEMISTRY 180-228 

I. The Urine . 180-216 

Definition, mechanism, 180; selection of a specimen, 181. 

Physical Properties. Description of normal urine, var- 
iability in health and in disease, quantity, 181 ; transparency, 
182; fluidity, color, odor, reaction, 183; acid and alkaline 
fermentations, 185. Specific gravity, 186; estimation of 
solids in. urine, 187. 

Normal Constituents. Urea, 188; methods of estimation, 
190-192. Kreatine, Kreatinine, Xanthine, Allantoin, Uric 
acid, 192; Coloring matters, 194; Phosphates, 195; Chlor- 
ides, 196; Sulphates, 197. 

Abnormal Urine. Albumin, 198; Tests: heat, nitric acid, 
Howe's, etc., 198; estimation, 199. Globulin, Albumose, 
Peptone, 200. Mucin, Sugar, 201; Tests: fermentation, 
201; alkali, alkali-copper, Fehling's, Haines', 202; alkali- 
bismuth, picric acid, indigo-carmine, phenyl-hydrazine, 203; 
estimation, 204; Acetone, Diacetic Acid, Calcium, Oxalate, 
205 ; Calcium Carbonate, Hippuric Acid, Bile, 206 : Test 
for bile coloring matters, 206; for bile salts, 207; Leucin, 
Tyrosin, Cystin, Blood, 208; Pus, 209; Fat, Epithelia, 210; 
Tube Casts, 211; Spermatozoa, Micro-organisms, 213; Ex- 
traneous Bodies, Calculi, 215. 
II. Milk 216-224 

Description, 216; (Colostrum, 216;) Chemical constituents, 
218. Casein, 218; Fat, Milk Sugar, 219; Salts, 220. 
Adulteration, 220. Milk Testing, 221 : hydrometer, lacto- 
scope, 221; centrifuge, Werner-Schmidt process, 222; clin- 
ical test, 224. Kumyss, 224. 

III. Saliva 224 

Description, function, ptyalin, potassium sulpho-cyanate, 224. 

IV. Gastric Juice 225-228 

Description, composition, pepsin, hydrochloric acid, 225. 
Test-meal, 225. Tests of stomach contents, 226 : litmus, 
congo-red, 226; free HC1 (Gunzburg's, Boas'), Uffelman's, 
rennet ferment, 227; butyric acid, acetic acid, 228; esti- 
mation of total acidity, of free HC1, of acid salts, 228. 

Ferments 229 

Table of Metric Measures 230 

Index 231 






THE 

ESSENTIALS OF MEDICAL AND 
CLINICAL CHEMISTRY. 



INTRODUCTION. 



" Chemistry is that branch of science which treats of the com- 
position of substances, their changes in composition and the laws 
governing such changes." (Webster.) 

The distinctive characteristic of chemical action is change in 
composition} A piece of iron may undergo many and marked 
changes ; it may be made hard or soft, hot or cold, luminous or 
non-luminous, magnetized or unmagnetized ; yet, so long as there 
is no modification of its composition, the change is not a chemical 
one, and the iron is still iron. But when it combines w T ith other 
substances, as in rusting (combining with the oxygen of the air), 
the change is chemical and a new substance is formed which, 
though it contains iron, is not iron, but is entirely different in 
composition and properties. 2 

NbTE. — It would be well for the professor or demonstrator at each labora- 
tory exercise to indicate beforehand, by means of the attached numbers, such 
of the experiments as he wishes performed. Each student should be required to 
have a note-book and make careful and full memoranda of everything he does. 

1 Heat pieces of platinum and magnesium wire. Note that while the 
platinum is unaltered, the magnesium burns (combines with the oxygen of the 
air) and is converted into a white powder. 

2 Suspend an ordinary hand-balance (Fig. i) from the upper ring of the 
retort-stand, so that the pans are about a half inch above a note-book laid on 
the lower and larger ring. 'Weigh out one gram of powdered iron; put it 
into a small dish made by bending up the edges and corners of a bit ol thin 

2 (9) 



IO 



ESSENTIALS OF CHEMISTRY. 



Matter is that of which the sensible universe is composed. It 
is Indestructible. Substances may undergo many changes, assume 
a great variety of forms, and even become invisible and fleeting 
gases; yet in none of these changes and combinations can a 
particle of matter be created or destroyed. 8 



Fig. i. 



Fig. 2. 





All matter has weight. By 
balances in the open air we 
get the apparent weight of a 
body ; but to obtain the ab- 
solute weight it must be 
weighed in a vacuum where 
there is no air to buoy it up. (For measures of weight, see 
table at back of book.) But of most importance to the student 
of chemistry is the specific weight or specific gravity, by which 
we mean the weight of a substance as compared with the weight 
of an equal volume of some other substance specified as a 
standard. It is not the weight of any particular body or piece of 
a substance, but the relative weight of that substance or material 



sheet iron or copper; heat it until it ignites. When combustion is complete, 
pour it again into the scale, and note that a new reddish-brown substance is 
formed, and that the weight is increased. 

3 Let the instructor burn a piece of charcoal (carbon) in a jar of oxygen gas 
(Fig. 2). It disappears, and, so far as we can judge by the senses of sight 
and touch, is lost, for it has combined with the oxygen to form an invisible 
gas. Add lime water and shake. The gas combines with the lime and forms 
a white precipitate, which, if gathered and weighed, would exactly represent, 
besides the lime, the charcoal burned and the oxygen required to burn it. 




INTRODUCTION. I T 

wherever found. The standard for liquids and solids is water ; for 
gases it is hydrogen or air. To determine the specific 
gravity of a liquid, divide the weight of a certain volume 
of it by the weight of an equal volume of water, and 
thus obtain the ratio. 4 

In practice we use : (a) The specific gravity flask 
(Fig. 3), made and marked to contain a certain number 
of grains or grams of water. Fill it up to the " scratch " 
on the narrow neck, with the liquid to be investigated, and weigh, 
deducting the weight of the flask. Divide the weight of the 
liquid by the marked capacity of the flask, (b) 
The hydrometer (Fig. 4), a hollow glass float 
with a graduated neck at the upper end indicat- dp^ 

ing the specific gravity by the depth to which it 
sinks in the liquid. 5 This instrument is often 
called by other names according to its use, as 
"lactometer" for milk and "urinometer" for 
urine. 

For very accurute measurements of specific 
gravity, the liquids must be at the standard tem- 
perature, which in this country is 6o° F. or 
i5-5 C 

The specific gravity of solids is determined on 
the principle of Archimedes : A body immersed in a liquid 
displaces its own volume, and loses weight equal to the weight 
of the liquid displaced. Therefore, the weight a body loses when 
weighed in water is the weight of its own volume of water, 

4 Procure a light vial or a small flask of 5 or 10 Cc. (1 or 2 drams) 
capacity, make a scratch on the neck with a file and weigh. Fill up to the 
scratch with water and weigh, deducting the weight of the vial, (a) Fill again 
with some liquid, as alcohol, lighter than water and weigh, deducting the 
weight of the vial. Divide the weight of the vialful of alcohol by the weight 
of the vialful of water. The resulting ratio will be the specific gravity of the 
alcohol, (b) Repeat the experiment, using sulphuric acid (a heavy liquid) 
instead of alcohol. 

5 Confirm the foregoing by using the hydrometer, first proving its accuracy 
by testing it in water and other liquids of known specific gravity. 



G. T/£.VAHfi-CD 



12 



ESSENTIALS OF CHEMISTRY. 



and the standard with which the weight of that body must be 
compared. 

In case the body is lighter than water, a sinker is attached and 

Fig. 5. 




the same method pursued, except that the loss of weight of the 
sinker is also obtained separately, and subtracted from the total 
loss to ascertain the loss of weight of the lighter body. 7 

6 Procure a small piece of metal, as a key, or better still, an iron " jack," 
such as children play with, and weigh it. Next suspend it by a fine silk thread 
from one pan of the balance (Fig. 5) into a beaker of water, and weigh it 
while completely immersed. For an example we will suppose : 

The piece of iron weighs 150 grains. 

Suspended in water it weighs 130 " 

Loss (or weight of its volume of water) 20 " 

Specific gravity of the iron (150-^-20) , . . . 7.5 

7 Secure a piece of a small spermaceti candle; weigh it alone, and then 



INTRODUCTION. 1 3 

A body soluble in water may be weighed in some liquid of 
known specific gravity in which it is insoluble. ^ 

The specific gravity of a substance in fine particles or powder 
may be determined by comparing its weight with the weight of 
the water it displaces in a vessel of known capacity. 9 

Matter exists in one of three states, solid, liquid, or gaseous. 
In the solid state the particles are held together so rigidly as to 
give the body a definite shape ; while in the liquid state the attrac- 
tion is so slight as to allow the particles to move freely upon each 
other and the body to take the shape of the vessel that contains 
it. In the gaseous state the mutual attraction of the particles is 

attach it to the piece of iron used in the previous experiment and weigh the 
combination, calculating the specific gravity as in the following example, in 
which we will suppose the candle weighs 85 grains: 

The combination (iron 150 grains and candle 85 grains) 

weighs 235 grains. 

The combination weighs in water 125 " 

Loss (the weight of the combination's volume of water), no " 
Deduct the weight of the piece of iron's " " " . 20 " 

The weight of the candle's volume of water . 90 " 

Weight of candle divided by weight of its water volume (85-^-90)= 
0.95—the sp. gr. of spermaceti. 

5 Make such an experiment as this: Suppose a lump of rock-candy weighs 
ico grains, and in turpentine 45.62 grains. Lcss=icc — 4;. 62=54.38 grains. 
100—54.38— 1.84 the sp. gr. as referred to turpentine. Multiply this by .87, 
the sp. gr. of the turpentine, and we get 1.6 as the true sp. gr. of rock-candy 
or crystallized sugar. 

9 Weigh out 50 grains of fine, clean, dry sand, such as is sold for canary 
birds, and pour it into the vial used in experiment 4. Fill with water and 
weigh: then calculate the specific gravity of sand as in the following example, 
in which the vial is supposed to hold just 96 grains of water : 

Weight of the sand - 50 grains. 

Weight of a vialf ul of water 96 u 

Total 146 " 

Weight of the vialf ul of water with the sand 124 " 

Weight of the water-volume of the 50 grains of sand - . . 22 " 
Weight of the sand divided by the weight of its water- 
volume (50^22-2.27) gives the specific gravity of 
sand ■ 2.27 



14 ESSENTIALS OF CHEMISTRY. 

entirely overcome, and their distance from each other depends 
upon the pressure to which the gas is subjected. The term fluid 
is applied to anything capable of flowing, whether liquid o 
gaseous. It is highly probable that all substances, which are not 
decomposed by heat or cold, are capable of existing in all three 
states. Heat is absorbed and hence cold produced whenever the 
attraction between the particles is to be overcome, as in the pass- 
age of a substance from the solid to the liquid or from the liquid 
to the gaseous state. 

When the two solids, ice and common salt, are mixed, they 
form a liquid, and great cold is produced. 10 Perspiration in 
evaporating assumes the gaseous state, and absorbs in the change 
so much heat that the body is kept at its normal temperature in 
spite of the hottest weather. 11 

On the other hand, when a substance passes from a rarer to a 
denser state it gives out again the heat absorbed in its passage in 
the opposite direction. 

If we examine the infinite variety of substances upon our earth 
we find most of them are compounds, i. e., they can be decom- 
posed into two or more other substances, distinct in their proper- 
ties from the substance from which they were derived and from 
each other. There are some substances which have never been de- 
composed. These are called elements. Only about seventy elements 
are at present known ; but, as our methods of investigation im- 
prove, this number may be increased by the discovery of other 
elements, or decreased by decomposing some of those now con- 
sidered elements. About one-half of these enter into the materia 
medica, and will be noticed in this work. 



10 Fold tin-foil into the shape of a little dish; add powdered ice and salt. 
Spill a few drops of water on the table and set the dish in it. Note how 
quickly it is frozen fast to the table. 

11 Pour a few drops of ether into the hand and note the cold produced by 
its rapid evaporation. Or let the instructor put a little water in such a dish as 
the one just mentioned, and throw a spray of ether against the sides;, the 
water is quickly frozen. 



INTRODUCTION. 



15 



TABLE OF ELEMENTARY BODIES, WITH THEIR SYMBOLS AND ATOMIC WEIGHTS. 
{The more imPorta?it are pri7ited in capitals.) 



Name. 



Aluminum, 

Antimony (Stibium), 

Argon, 

Arsenic, 

Barium, 

Bismuth, 

Boron, 

Bromine, 

Cadmium, 

Qesium, 

Calcium, 

Carbon, 

Cerium, 

Chlorine, 

Chromium, 

Cobalt, ... 

Columbium (Niobi- 
um) 

Copper (Cuprum), 

Erbium, 

Fluorine, 

Gadalinium, 

Gallium, 

Germanium, 

Glucinum (Ben- Ilium, 
Be) 

Gold (Aurum),. 

Helium, 

Hydrogen 

Indium, 

Iodine, 

Iridium, 

Iron (Ferrum), . 

Lanthanum, .... 

Lead (Plumbum, 

Lithium, 

Magnesium, . . . 

Manganese, 



Symbol. 


Atomic 
Weight. '■ 


Al 


27 


Sb 


120 


A 


40 


As 


75 


Ba 


137 


Bi 


208 


B 


11 


Br 


80 


Cd 


112 


Cs 


*33 


Ca 


40 


C 


12 


Ce 


132 


CI 


35- 


Cr 


52 5 


Co 


59 


Cb 


93 


Cu 


634 


E 


166 


F 


19 


Gd 


157 


Ga 


70 


Ge 


72 


Gl 


9 


Au 


197 


He 


4.26, 


H 


1 


In 


114 


I 


127 


Ir 


193 


Fe 


56 


La 


« 39 


Pb 


207 


Li 


7 


Mg 


24 


Mn 


55 



Name. 



Mercury (Hydrargy- 
rum) , 

Molybdenum. 

Neodymium, 

Nickel, 

Nitrogen, 

Osmium, 

Oxygen, 

Palladium, 

Phosphorus, 

Platinum, 

Potassium (Kalium), 

Praseodymium, 

Rhodium, — 

Rubidium, 

Ruthenium, 

Samarium, 

Scandium, 

Selenium, 

Silicon, 

Silyer (Argentum),. 
Sodium (Natrium),.. 

Strontium, 

Sulphur, 

Tantalum, 

Tellurium, 

Terbium, 

Thallium, 

Thorium, 

Tin (Stannum), 

Titanium, 

Tungsten, or Wolfram 

Uranium, c 

Vanadium, 

Ytterbium, 

Yttrium, 

Zinc, 

Zirconium, 



q tt „ v 1 Atomic 
Symbol. Weight> 



Hg 

Mo 

Nd 

Ni 

N 

Os 

O 

Pd 

P 

Pt 

K 

Pr 

Rh 

Rb 

Ru 

Sm 

Sc 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Te 

Tb 

Tl 

Th 

Sn 

Ti 

W 

U 

V 

Yb 

Y 

Zn 

Zr 



200 

96 
141 

59 

14 
191 

16 
106 

3i 
J95 

39-i 
144 

104 

85 

101 

l S° 

44 

79 

28 
108 

23 

87.5 

32 
182 
125 
160 
204 

233 
118 

5° 
184 
240 

5 J -2 
*73 

90 

65 
90 



To explain the laws governing chemical phenomena, modern 
chemistry has adopted and greatly amplified the old atomic 
theory — a theory advanced certainly as far back as the ancient 
Greeks, for Democritus, 460 B. C, said : "The atoms are invisible 



1 6 ESSENTIALS OF CHEMISTRY. 

by reason of their smallness ; indivisible by reason of their solid- 
ity; impenetrable and unalterable." 

We will take up the theories and laws, not in the order of their 
enunciation, but of their natural sequence. 

It is assumed that matter is composed ultimately of infinitely 
small particles called atoms ; that each element is composed of 
atoms, all of a certain size, weight, etc. Atoms rarely exist alone, 
but in groups called molecules. In an element the molecule is 
generally composed of a pair of atoms of the same kind ; in com- 
pounds, of two or more atoms of different kinds. It has been de- 
termined that equal volumes of all substances in the gaseous state, 
and under like conditions, contain the same number of molecules. 
So a gallon of hydrogen gas and one of oxygen gas contain the 
same number of molecules, and those molecules consisting of pairs 
of atoms, each gallon must contain the same number of atoms. 
Furthermore, it is found that the gallon of oxygen is sixteen times 
as heavy as the gallon of hydrogen. So each oxygen atom must be 
sixteen times as heavy as the hydrogen atom. Hydrogen being the 
lightest substance known, its atomic weight is taken as i, and con- 
sequently the atomic weight of oxygen is 1 6. The atomic weights 
of other elements are determined in a similar way. By " atomic 
weight" is not meant the absolute weight of atoms (for that is not 
known), but the weight of the atom compared with the hydrogen 
atom. The atomic weight of carbon is 12. If carbon combines 
with oxygen, atom for atom, the new substance (CO) resulting 
from that action will consist of molecules, in each of which the 
carbon will weigh 12 and the oxygen 16, and, as the whole mass 
is composed of these molecules, the same proportion obtains 
throughout the new compound. So 12 is found to be the com- 
bining weight of carbon, and 16 of oxygen. If, however, the 
combination should occur in the proportion of one atom of 
carbon to two atoms of oxygen, then each molecule must consist 
of 12 by weight of carbon to 32 of oxygen, and that must be the 
proportion throughout the entire substance. 

Between these two compounds of a carbon atom with oxygen 



INTRODUCTION. 1 7 

no intermediate one can occur, for the carbon atom must take one 
or two, or more, oxygen atoms. It cannot take a fraction of one, 
for atoms are indivisible. Hence, we deduce the following Law : 
Substances combine in certain fixed proportions (atomic weights) 
or in multiples of these proportions. 

Symbols are abbreviations of the names of the elements. They 
consist of the initial letter of the Latin name ; but if the names of 
several elements begin with the same letter, the single-letter sym- 
bol generally is reserved for the most common element, and for 
the others another letter is added. Thus, we have nine elements 
whose names begin with C ; the most common is carbon, whose 
symbol is C ; the others add other letters, as chlorine, CI ; cobalt, 
Co j copper (cuprum), Cu, etc. The symbol indicates just one 
atom. When more than one atom is to be represented, the num- 
ber is written just after and below the symbol, thus, C 4 . 

Formuloz are to molecules what symbols are to elements. They 
indicate the kind and number of atoms composing the molecule. 
When more than one molecule is to be indicated, the number is 
placed in front of the formula, thus, 5H9O. A parenthesis in- 
closing several symbols or formulae should be treated as a single 
symbol, thus, 2(NH 4 ) 2 C0 3 = N,H 16 C 2 6 . 

An equation is a combination of formulae and algebraic signs to 
indicate a chemical reaction and its results. As no matter is ever 
lost or created in a reaction, the number of each kind of atom 
before the equality sign must be the same as after it. 



PART I.— INORGANIC CHEMISTRY. 



Classification of the Elements. — The elements are usually 
divided into two great classes : (a) Metals, about fifty-five in 
number, possessing a peculiar lustre, good conductors of heat and 
electricity, and whose oxides when combined with water, form 
bases; (b) Non-metals, about fifteen in number, possessing but 
little lustre, relatively poor conductors of heat and electricity, and 
whose oxides combined with water form acids. The following 
classification is somewhat arbitrary, but convenient, and based 
mainly on chemical analogies, especially in valences and atomic 
weights. 

I. Preliminary Group : Hydrogen and Oxygen. 
II. Chlorine Group: Fluorine, Chlorine, Bromine, and 
Iodine. 

III. Sulphur Group: (Oxygen) Sulphur, Selenium and Tel- 
lurium. 

IV. Nitrogen Group: Nitrogen, Phosphorus, Arsenic, Anti- 
mony and Bismuth. 

V. Carbon Group: Carbon, Silicon, Tin, Lead, Platinum, 
Iridium, Osmium, Palladium, Ruthenium and Rhodium. 

VI. Potassium Group: Lithium, Ammonium, Sodium, Potas- 
sium, Rubidium and Caesium. 

VII. Calcium Group: Calcium, Strontium and Barium. 
VIII. Magnesium Group:. Magnesium, Zinc and Cadmium. 
IX. Aluminum Group: Boron, Aluminum, Scandium, Gal- 
lium, Yttrium, Indium, Lanthanum, Cerium, Neodymium, Praseo- 
dymium, Samarium, Erbium, Ytterbium and Thallium. 

X. Iron Group: Chromium, Manganese, Iron, Cobalt, 
Nickel, Molybdenum, Tungsten and Uranium. 

XL Copper Group: Copper, Mercury, Silver and Gold. 
(,8) 



PART I. INORGANIC CHEMISTRY. 



T 9 



I. The Preliminary Group : 

Hydrogen. 
Oxygen. 

The elements of this group have but little in common. Oxygen 
belongs to the sulphur group, while Hydrogen, the " type-element," 
is a group to itself; but because of their intimate, extensive and 
important relations with the other elements, as well as the 
familiar character of their combinations with each other, we group 
them together as a fit beginning of the study of Chemistry. 



Fig. 6. 





HYDROGEN (H — i). — It occurs in nature occasionally un- 
combined, as in gas-wells and volcanoes ; but in the combined 
state it forms one-ninth of the water on the globe, and is the base 
of all acids as w T ell as a constituent of nearly all organic matter. 
Prepared in various ways from its compounds, e. g. 9 (a) by de- 
composing water with the electric current (see Fig. 14) ; (b) by 
displacing the hydrogen from water by means of metallic sodium " l3 



12 Into a tumbler half filled with water (Fig. 6) drop a piece of sodium the 
size of a pea. The metal melts and dances around with a hissing noise, get- 
ting smaller and smaller until it disappears with a sudden snap, the spattering 
from which should be anticipated by covering it with a piece of card-board. 

13 Repeat the above, except that the sodium is caught in a gauze spoon and 



20 ESSENTIALS OF CHEMISTRY. 

or potassium (H 2 OH-Na^NaHO+H), or by means of other 
metals with the aid of heat, or (c) by displacing hydrogen from 
acids by means of a metal, as zinc 14 (H 2 S0 4 -f Zn=ZnS0 4 +H 2 ). 

Physical Properties, — A gas, transparent and colorless, and 
when pure, odorless and tasteless ; the lightest substance known, 
fourteen and a half times as light as air ; hence used for bal- 
loons. 15 Very diffusible ; hence hard to keep from leaking. Acts 
in many respects like a metal, displacing metals in chemical com- 
pounds, seeming to form alloys with certain metals, and a con- 
ductor of electricity. Hydrogen was condensed to a liquid in 
1898, by Dewar. It is by far the lightest liquid known, having a 
specific gravity of 0.07 ; boils at — 238 C. ( — 396 F.), at ordinary 
atmospheric pressure, and at — 250 C. ( — 418 F.), in vacuo. 

Chemical Properties. — Hydrogen does not support ordinary 
combustion or animal respiration, but is not poisonous. It burns 
in air with a pale but very hot flame. With pure oxygen it forms 
the oxyhydrogen flame. This is the hottest flame known, and a 
stick of lime held in it glows with dazzling brilliancy, forming the 
calcium or Drummond light. Mixed with air or oxygen, it ex- 
plodes violently on contact with a spark. 16 

pushed down beneath the mouth of a filled and inverted test-tube, allowing 
the gas to bubble up in the tube and displace the water. Tubefuls may then 
be studied, e. g., (a) Show its lightness and combustibility by turning up a 
tubef ul a few inches beneath a flame ; the gas rising and coming in contact 
with the flame, ignites with a slight explosion, (b) To show that it is com- 
bustible, but not a supporter of combustion, bring a lighted match to the 
mouth of the tube; the gas ignites and burns quietly at the open end, but the 
match is extinguished when passed farther up into the gas, and is relighted 
again as it is withdrawn. 

14 Fill a side-neck test-tube one-third full of dilute (10 per cent.) sulphuric 
acid; add several bits of zinc; close its mouth with a cork, and attach 
a delivery-tube as in Fig. 7. Wait until the air is expelled, and then ignite 
the gas as it issues, or collect it over water, and test it as in the previous ex- 
periment. 

15 Attach an ordinary clay pipe to the delivery-tube of the hydrogen gen- 
erator and blow hydrogen soap bubbles; they rise in the air. 

1H Let the demonstrator fill a bladder or rubber bag with two parts of hydro- 
gen and one of oxygen or five of air; attach a tube and blow up soap bubbles 
in a basin. Touched with a flame, they explode. 



PART I. INORGANIC CHEMISTRY. 



21 



OXYGEN (O — 16).— Occurrence. Most abundant of the 
elements, comprising one-fifth of the air, eighth-ninths of water, 
one-half of the crust of the earth, and three-fourths of all 
organized bodies. 

Preparation. — Made most easily by heating potassium chlorate 

Fig. 8. 




(Fig. 8), and decomposing it into potassium chloride and oxygen, 
thus : 

KC10 3 = KC1 + 3O. 17 

Physical Properties. — A colorless, odorless and tasteless gas, a 
little heavier (t.io times) than air. Under a pressure of 22.5 
atmospheres and at a temperature of — 136 C, it condenses into 



17 Grind in a mortar some potassium chlorate with half as much manganese 
dioxide, a black powder that facilitates the evolution of the oxygen. Heat this 
10 a side-neck test-tube as in Fig. 8, or in an open test-tube. Recognize the 
oxygen by the energetic combustion when a match, or even the glow r ing end 
of the charred stick is introduced. 

Note. — Experiments 18, 19 and 20 are to be performed by the instructor. 



22 



ESSENTIALS OF CHEMISTRY. 



Fig. 9. 




Fig. 10. 



a colorless liquid (sp. gr. of 0.899). Water dissolves only three 
volumes to the hundred, but this is enough to sustain aquatic life. 
Chemical Properties, — Intense affinities ; combines with every 
element except fluorine. The product 
of its action is called an oxide, and the 
process oxidation. Oxidation so rapid as 
to produce heat and light is called com- 
bustion; if no 
light, slow com- 
bustion. Sub- 
stances that 
burn in air 
burn more bril- 
liantly in oxygen, 18 and many sub- 
stances that do not burn in air will 
burn in this gas. 19 By this property 
oxygen is usually recognized and dis- 
tinguished from most other gases. 

Oxygen, especially in its diluted 
form (air), is the great supporter of 
combustion, for which its abundance 
and universal presence eminently fit it. 
Combustible and supporter of com- 
bustion are only relative terms. When 
a combustible substance burns in a 

supporter of combustion the union is mutual, one being as much 
a party to the action as the other. A jet of air or oxygen burns 




18 A bit of phosphorus, dried by pressing between folds of blotting paper, is 
placed in a combustion spoon, ignited, and lowered into a jar of oxygen. 
The combustion is so intense that the phosphoros volatilizes, and its vapor 
burns throughout the jar with a brilliancy so dazzling that it is called the 
" phosphorus sun." 

19 A watch-spring is wound into a spiral, tipped with a bit of tinder or a 
piece of yarn dipped in sulphur. This is lighted and lowered into a jar of 
oxygen. (Fig. 9.) The iron catches fire and burns with brilliant scintilla- 
tions, globules of melted iron falling and melting into the glass, unless the 
bottom be covered with sand or water. 



PART I. — INORGANIC CHEMISTRY. 23 

as readily in coal gas as a jet of coal gas barns in air or oxygen. 20 
The one in greatest abundance is usually called the supporter of 
combustion. 

Oxidizing agents are compounds in which oxygen is held so 
feebly it is readily given up to substances having greater affinity 
for it. 

Uses. — The process of respiration is a species of combustion, 
and, as oxygen is the best supporter of combustion, it is the 
best (and only) supporter of animal respiration. Administered 
in capillary bronchitis, oedema glottidis, etc., when the patient 
cannot take in a volume of air sufficient to supply the requisite 
amount of oxygen, it has saved many lives. 

OZONE. — If through a portion of air or oxygen, electric sparks 
be passed, a part of the oxygen will acquire a pungent odor and 
peculiar properties. This may be observed about most electrical 
apparatus, especially X-ray machines, or, better still, the Siemens 
ozone tube. 21 

The same change may be induced by various chemical pro- 
cesses, e. g., by mixing permanganate of potassium and sulphuric 

20 Secure an ordinary lamp chimney (Fig. 10) and a wide cork to fit its lower 
end. Pass through the cork a narrow tube (#) connected by rubber hose 
with the house gas, and a wider one opening into the air. Turn on the coal 
gas and light it as it issues from the tube. The cork with the flame (not too 
large) is then inserted into the chimney, where it continues to burn, sufficient 
air entering through the wide tube (<:). Upon turning on more gas the air is 
crowded out and the chimney filled with coal gas. The gas flame disappears 
from the tube (#), and an air flame appears upon the tube (<:) as the entering 
air burns in the atmosphere of coal gas. The excess of coal gas may also be 
lighted as it escapes, showing a gas flame above and an air flame within the 
chimney. On lessening the flow of gas the air will again be in excess, and the 
flame again appear on the narrow tube (a). In the gas flame above the lamp 
chimney heat some potassium chlorate in a combustion spoon until it melts 
and oxygen begins to bubble up. Then lower it into the atmosphere of coal 
gas within the chimney. The escaping oxygen burns brilliantly, the coal 
gas being the supporter of the combustion. 

21 Siemens' apparatus for ozoning oxygen (Fig. 11) consists of two tubes, 
the inner surface of the inner and the outer surface of the outer tube being 
coated with tin -foil, and each connected with the poles of an induction coil 
or Toepler-Holtz machine. A current of oxygen passing between these tubes 
may be ozoned to the extent of fifteen or twenty per cent. 



24 



ESSENTIALS OF CHEMISTRY. 



acid, or when phosphorus partially covered with water is exposed 
to the air. This modified oxygen is called ozone. It is one and 



Fig. ii. 




Fig. 12. 



a half times as heavy as ordinary oxygen, for its molecule contains 
three instead of two atoms. Very energetic, oxidizing substances 
unaffected by ordinary oxygen. Oxidizes potassium iodide with 
liberation of iodine, hence its test : paper dipped in a solution of 
potassium iodide and starch is colored blue 
in the presence of ozone." 2 Ozone is found 
in the air, especially after thunder storms, 
and when present in considerable amount 
(as much as .00005 per cent.) is apt to irri- 
tate the respiratory tract ; but by oxidizing 
infecting germs, etc., it prevents the spread 
of infectious diseases. 

The various preparations known as " ozon- 
ized ether," "ozonized water," " pyrozone," 
etc., are mainly solutions of hydrogen diox- 
ide. 




Into a beaker place some crystals of potassium permanganate. Suspend 
on a glass rod, as in Fig. 12, a strip of ozone test-paper, and beside it a strip 
of plain white paper for comparison. Pour from a pipette on the crystals a 
few drops of sulphuric acid. Cover with a card-board, and note the gradual 
blueing of the test paper by the ozone. 



PART I. INORGANIC CHEMISTRY. 



25 



COMPOUNDS OF HYDROGEN AND OXYGEN. — Two 

of these are known : 

Hydrogen Monoxide, H 2 0. 
Hydrogen Dioxide, H 2 2 . 

Hydrogen Monoxide or Water. — Occurrence, — Water is seen 
almost everywhere in nature, yet much is invisible, as in the air, 



Fig. 13. 





and hidden, as in crystals, etc. ; it constitutes the major part of 
all plants and animals. 23 

Physical Properties, — Transparent, colorless, odorless, tasteless 
liquid. Below 32 F. (o° C.) it is a solid (ice), and above 212 
F. (ioo° C.) a vapor (steam or vapor of water). In solidifying, 

2i Melt a 5-inch piece of glass tubing into two portions, and then heat the 
closed ends, and blow them into slight bulbs. Into one introduce a bit of 
match stick and heat. Note (a) water of constitution, (£) residue, and (V) 
that this is destructive distillation. 



26 ESSENTIALS OF CHEMISTRY. 

water expands ; so ice floats. The boiling-point is higher than 
2i2° F. under increased pressure or when it contains solid matter 
in solution; and lower than 212 F. when the pressure is dimin- 
ished as in vacuum-pans and at high altitudes. 

Chemical Properties. — The chemical composition of water 
may be proved by {synthesis) combining its constituents 
(H 2 -f = H 2 0) 2i or by {analysis) passing the galvanic current 
through water until it is decomposed into its component gases 
( H 2 = H 2 + O ) , 25 Neutral in reaction ; combines with the 
oxides of the metals to form hydrates (bases), and with the 
•oxides of the non-metals to form acids. 

Uses. — Water is the greatest of all solvents, and thus performs 
an important function in the economy of nature and human arts. 
It is the vehicle by which all foods and drugs must reach the 
tissues and the waste products leave them. Most chemicals are 
used in aqueous solutions, and medicines are generally adminis- 
tered dissolved with water. The watery solution of a fixed sub- 
stance is called a "liquor" and of a volatile substance an "aqua" 

One body is said to dissolve in another when they coalesce and 
their particles intimately mingle. This is possible only in the 
liquid and gaseous states. When a substance dissolves it takes on 
the physical state of the solvent, e. g., a solid or gas dissolving in 
water becomes a liquid and then mixes with the water, the gas ele- 
vating the temperature and the solid lowering it. Heat assisting the 
liquefaction of a solid, and opposing that of a gas, generally hastens 
the solution of the one and retards that of the other. Many solid 
substances when separating from a solution take with them, as a 
necessary part of the crystal, a certain definite amount of water — 
water of crystallization. This water does not modify the chemi- 

Note. — Experiments 25 and 26 had best be performed by the instructor. 

2 * A mixture of two volumes of hydrogen and one of oxygen exploded in a 
eudiometer (Fig. 13), produces only water. 

25 Fill the apparatus shown in Fig. 14 with water acidulated with sulphuric 
acid. Connect with a battery. The electricity passing through the water 
decomposes it into two volumes of hydrogen which collects in one tube and 
one volume of oxygen in the other. 



PART I. — INORGANIC CHEMISTRY. 27 

cal nature of the substance, but is necessary for maintaining the 
crystalline form. If the crystal loses its water of crystallization 
by heat or exposure, it effloresces into an amorphous powder.' 6 
Some substances when exposed absorb water from the air and 
deliquesce (melt down). 

Natural Waters are never pure, since water dissolves more or 
less of almost everything it touches ; the air through which it falls 
as rain, the surfaces over which it flows and the strata through 
which it percolates, each adding its quota to the contamination. 
Good, potable (drinkable) water should be cool, clear and odor- 
less, with just gases and solids enough in solution to give it an 
agreeable taste, neither flat, salty nor sweetish, and should dis- 
solve soap without an appreciable curd. Yet a water may be all 
this and be unpotable from the presence of poisonous and in- 
fectious contamination. Rain and snow water are the purest of 
natural waters, except in the neighborhood of large cities where 
the air is impure and the roofs dirty. Melted ice is purer than the 
water from which it is formed, since most of the dissolved solids 
remain in the unfrozen water; but the suspended matters are re- 
tained, many of the bacteria, especially typhoid, passing through 
the ordeal uninjured. Like boiled water it has a flat taste from 
the loss of dissolved gases. Most cities get water from rivers and 
lakes, while country people usually obtain theirs from springs and 
wells. Well water in cities, and even in small towns where the 
ground is more or less saturated with filth from cess-pools, drains 
and surface accumulations, is always more or less contaminated 
and dangerous, though its sparkle and agreeable taste often com- 
mend it to those using it. A well is often what Larrabee used to 
call "a perpendicular drain," and is especially dangerous if shal- 
low. Deep wells are such as are ioo feet or more in depth or 
draw their water from beneath a stratum of impervious clay or 
rock. These waters from contact with the earth contain min- 

26 Into the other tube drop a small crystal of CuSO^H^O. Pleat gently and 
note [a) water condensed in cooler part of the tube and (b) the residue is 
amorphous. 



2 8 ESSENTIALS OF CHEMISTRY. 

eral matters, especially salts of calcium and magnesium, making 
them more or less hard. The character of the mineral impurities 
is easily determined by their appropriate tests, and the total 
amount estimated by evaporating carefully (over a water-bath) a 
certain volume of the water and weighing the residue, which 
should never be over 30 or 40 grains to the gallon. But a vastly 
more important and dangerous contamination is organic, espe- 
cially nitrogenous and animal matters; not that these organic 
matters are themselves so dangerous, but that they form a favor- 
able soil, a nidus for the development and growth of various 
infecting germs that may be implanted therein, as during epidem- 
ics of cholera, dysentery and typhoid fever. Such water is a 
prolific source of disease, and its use is never safe. The recog- 
nition of the presence, number and character of these organisms 
is the province of the bacteriologist and requires such special care 
and skill, and offers so many difficulties that chemical methods 
are usually relied on to show the presence of the organic matter 
without which the germs cannot exist. 

The more exact methods of testing for organic contamination 
are so complex that they are practicable only to the chemist, but 
the physician may easily do it m a rough and ready way : — 

(a) Half fill a clean bottle with the water; warm, agitate and 
critically smell it ; a foul odor indicates organic impurity. 

(b) To 100 Cc. of the water add 1 Cc. of sulphuric acid ; warm 
and add a few drops of a 1 per cent, solution of potassium per- 
manganate ; the rose color imparted by the latter is destroyed if 
organic matter be present. 27 

Mineral Waters are such as possess real or supposed special 
therapeutic value, and may be classed as follows : 

(a) Carbonated, those charged with carbonic acid (carbon 
dioxide) . 



27 Various substances other than organic matter will produce the same effect, 
but since they are usually produced from the oxidation of nitrogenized and 
sulphurized organic matter they too point to previous pollution. 



PART I. — INORGANIC CHEMISTRY. 29 

(b) Sulphur, containing some soluble sulphide, especially 
hydrogen sulphide. 

(c) Alkaline, those containing soluble alkalies such as carbon- 
ates or bicarbonates of sodium and potassium. 

(a) Lithia, such as contain salts of lithium, even when in very 
small amount, and associated with other substances. 

(e) Saline, those containing neutral salts such as the chlorides, 
bromides and sulphates of sodium, magnesium, etc. 28 

(/) Chalybeate, which contain some compounds of iron, 
usually the carbonate held in solution by carbon dioxide and 
depositing when that gas is lost on exposure to the atmosphere. 

(g) Thermal or natural hot waters ; useful mainly for baths. 

Many waters belong to more than one class, as alkaline-carbon- 
ated, alkaline lithia, etc. 

Purification of Water. — Natural waters may be purified by 

(a) Boiling, which sterilizes the water by destroying the living 
organisms and precipitates the carbonates of calcium, magnesium 
and iron by driving off the carbon dioxide holding them in solu- 
tion. 

(b) Filtration, that is, passing it through some clean, insoluble, 
porous substance as paper, charcoal, sand, brick, stone or un- 
glazed earthenware. Some filters, if well made and clean, will 
remove not only the suspended matters, but a considerable por- 
tion of the dissolved organic substances. Filters of unglazed 
porcelain are sold which remove all micro-organisms and yield a 
water perfectly sterile. Many cities now have their water sup- 
plies filtered through clean, sharp sand; and experiments have 
shown that " A sand filter 5 feet thick and filtering two million 
gallons per acre a day will remove 99.98 per cent, of the bac- 
teria," and that the most polluted waters can thus be rendered 
almost harmless. 

(c) Distillation in which the water is boiled and its vapor 



2K Sea water is a saline water containing about 3J& P er cent, of mineral 
matter, mainly sodium chloride, with smaller quantities of other mineral salts. 



3° 



ESSENTIALS OF CHEMISTRY. 



passed through a block-tin or glass condenser as shown in Fig. 
15, and recondensed and gathered in a clean vessel. 29 Where 



Fig. 15. 




great purity, is required as in the preparation of the officinal dis- 
tilled water (aqua destillata U. S. P.), the first 10 per cent, is 
rejected as liable to contain the gaseous impurities, and the last 
10 per cent, left in the boiler, lest some of the more volatilizable 
solids come over with it. so 

Hydrogen Dioxide. — Peroxide of Hydrogen (H 2 2 ) . Prepared 
most easily by passing C0 2 through barium dioxide in suspended 
in water, thus : 

BaO a +CO a +H a O=BaC0 3 +H 2 O a , 

or commercially by hydrofluoric acid thus : 

Ba0 2 + 2 HF-BaF 2 + H 2 2 . 



yy Dissolve 1 Gm. of CuSO in water and boil in a stoppered side-neck test- 
tube (Fig. 16) introducing the delivery tube into a clean test-tube set in a 
beaker of crushed ice. Note the absence of taste, color, etc., in the distillate. 

x0 If a solid be so treated the process is called sublimation instead of distil- 
lation; and the product is a sublimate instead of a distillate. When a mixture 
of two or more liquids is distilled, the one having the lowest boiling point 
comes over first, leaving the others behind; and the process is called frac- 
tional distillation, but the separation is seldom complete. 



PART I. INORGANIC CHEMISTRY. 3 1 

The insoluble barium salt may be allowed to subside, and the 
clear aqueous solution of H 2 2 poured off. It is sold in various 
strengths, according to the number of volumes of oxygen a certain 
volume of the solution will yield, the ten-volume solution being 
most employed. The so-called u Ozonized ether " is made by 
shaking this solution with ether, which extracts the hydrogen 
dioxide. 

Properties. — When concentrated, hydrogen dioxide is a color- 
less, syrupy liquid of pungent odor and taste, and decomposes 
so easily into H 2 + that it must be kept in a cool place, well 
bottled, in acid solution, away from contact with organic matter, 
and agitated as little as possible. 

Uses. — Being an active oxidizer, 81 it is a valuable bleaching 
agent, 33 especially for woolen fabrics, and is largely sold as 
blondine for bleaching the hair. As it destroys bacteria and dis- 
solves pus, etc., it is used very abundantly in medicine and surgery 
to cleanse ulcers and abscesses, and to dissolve the membranes of 
scarlet fever, diphtheria, etc. As it effervesces with pus, 34 it is 
used as a test for pus in the urine. 

RADICALS. — Every molecule is composed of two parts, 
called radicals, held together by chemical affinity. Both 
radicals may be elements, as in H — CI, or one may be 
elementary and the other compound, as H — N0 3 , or both 
compound, as NH 4 — N0 3 . Some compound radicals can be 
isolated, e. g n by heat: Hg — CN = Hg+CN. Others decom- 
pose whenever set free. 

31 Take a little hydrogen dioxide solution, add a drop each of potassium 
chromate and sulphuric acid and a little ether, and shake; the potassium 
chromate is oxidized with the production of blue perchromic acid. 

32 Secure an old painting darkened with age, or an old engraving yellowed 
and soiled; wash it with hydrogen dioxide, and note the brightening effect. 

33 Dip a strip of ozone test paper into a solution of hydrogen dioxide, and 
note that it is not blued until a few drops of ferrous sulphate is added to act 
as an oxygen carrier. 

34 Add hydrogen peroxide to milk in test-tube and note effervescence, the 
cells in the milk acting as would pus corpuscles. 



32 ESSENTIALS OF CHEMISTRY. 

Often when a galvanic current is passed through a com- 
pound, the chemical affinity is overcome by the electricity, 
and the molecule separates into its two radicals, one of 
which goes to the positive and the other to the negative 
pole. 35 Unlike electrical conditions attract, so the radical 
going to the negative pole must be electro-positive, and the 
one going to the positive pole electro-negative. The metallic 
radicals are relatively electro-positive and the non-metallic 
electro-negative. 

Some radicals are more intensely electro-negative or 
electro-positive than others. In the following list the more 
common elements are so arranged that each is usually posi- 
tive to those following it and negative to those preceding : 

Positive end : -f K, Na, Mg, Zn, Fe, Al, Pb, Sn, Bi, Cu, Ag, Hg, 

Pt, Au, H, Sb, As, C, P, S, N, I, Br, CI, F, O.— Negative end. 

A radical is electro-positive or electro negative only in its 
relation to other radicals ; for while C is positive to O, it is 
negative to K. 

In formulas the electro-positive radical is written first and 
the electro-negative next. 

The greater the difference between the electrical condi- 
tion of two radicals, the greater the energy with which they 
unite and the more stable the product, and vice versa; e.g., 
O has a strong affinity for K, a weak one for*Cl, and will 
not unite with F under any circumstances. An idea once 
prevailed that the relation of affinities were fixed and con- 
stant between the same substances, and great pains were 
taken to construct tables similar to the above to show what 

35 Into a jar put some water; add solutions of red litmus, potassium 
iodide, and boiled starch ; connect with the galvanic battery. The 
electric current decomposes the potassium iodide into iodine, which 
gathers at the positive pole, producing a blue color, with the starch, and 
potassium at the negative, where it produces alkali, turning the red 
jitmus blue. 



PART I. — INORGANIC CHEMISTRY. 33 

was called the " precedence of chemical affinities." These 
tables showed the order of affinities for the circumstances 
under which the experiments were made, and nothing else. 

The circumstances attending chemical reactions are so 
complicated that in many cases it is impossible to predict 
the precedence of affinities and the result of an untried 
experiment. 

Among these modifying causes may be mentioned : 

1. Temperature, changes of which often reverse chemical 
affinities. Moderately heated, mercury and oxygen will 
readily combine, but when highly heated their affinity is 
destroyed, and they will refuse to unite, or, if already com- 
bined, will separate. 

Ordinarily free carbon has no affinity for oxygen, but at 
high temperatures it surpasses most other elements in its 
greediness for that substance, even taking it from a metal 
so extremely electro-positive as potassium. 

2. Volatility. — Whenever in a mixture of two or more sub- 
stances it is possible, by a re-arrangement of the radicals, to form 
a compound volatile at the temperature of the experiment, such re- 
arrangement will occur and the volatile compound be formed. 
For example : 

FeS+H 2 SCV=FeS0 4 +H 2 S ; or, 

2NH 4 Cl-f CaC0 3 =(NH 4 ) 2 C0 3 +CaCl 2 ; or, 

H 3 B0 3 +3NaCl=3HCi+Na 3 B0 3 . 

3. Insolubility. — Whenever, on mixing two or more substances 
in solution, it is possible, by re-arrangement of the radicals, to 
form an insoluble compound, that re-arrangement will occur and 
the insoluble compound be formed as a precipitate. For example: 

CaCl 2 +(NH 4 ) 2 CO s =CaC0 3 +2NH 4 Cl. 

It is especially important to remember this principle, for 
its application in tests, incompatibilities, and antidotes. 

4. Nascent State. — Ordinarily the atoms of an element are 



34 ESSENTIALS OF CHEMISTRY. 

grouped in pairs, and hence somewhat indifferent to the 
attractions of other atoms ; but just as they are being liber- 
ated (born) from a compound they are alone, and each atom, 
having no fellow, readily enters into combination with any 
atom it meets. This state is called nascent (nasci, to be born). 

5. Catalysis, — This is the name given to the unexplained 
influence exerted by some substances of inducing chemical 
reactions between other substances without themselves 
undergoing any change. 

The VALENCE of a radical is its combining value, or its 
value in exchange for other radicals. Stt Here again hydro- 
gen is taken as the standard. A radical that combines with 
or takes the place of one atom of hydrogen is said to be 
univalent (one valued); of two atoms, bivalent; three, triva- 
lent ; four, quadrivalent ; five, quinquivalent ; six, sexivalent. 
The valence is indicated by a Roman numeral just above 
and after the radical, thus: (NHJ 1 , Ca 11 , (P0 4 ) m , Si IV , As v , 
S VI . The two radicals of every saturated compound must 
possess an equal number of valences. Hence, 

In HC1 the radical CI is equivalent to 1 atom of hydrogen; 

In H 2 the radical O is equivalent to 2 atoms of hydrogen; 

In NH 3 the radical N is equivalent to 3 atoms of hydrogen; 

In CH 4 the radical C is equivalent to 4 atoms of hydrogen. 
Therefore CI is univalent, O bivalent, r trivalent, and C 
quadrivalent. 

The same regard for valence is observed when radicals 
are made to displace each other, thus: H (S0 4 ) n requires 
two atoms of K 1 or one of Zn 11 to form K^SOJ 11 or 
Zn n (S0 4 ) n . 

Some elements exercise more than one valence : e. g., 
mercury may be univalent, as in Hgl, or bivalent, as in 

36 The student should bear in mind that valence has nothing to do with 
the combining weight or the chemical activity of an element. 



PART I. INORGANIC CHEMISTRY. 



35 



Hgl 2 ; or iron may be bivalent, as in FeCl 2 , or trivalent, 
as in FeCl 3 . The termination " -ous" is given to those 
compounds in which the positive element exercises its lower- 
valence, and " -iV" to those in which the higher valence is 
exercised, as FeCl 2 , ferrous chloride ; and FeCl 3 , ferric 
chloride. 

In the following table the most commonly occurring simple 
or elementary radicals are arranged according to their 
valences : 

Table of Valence. 



I. 


II. 


III. 


IV. 


V 


VI. 


F, CI . . 


Ba, Sr . . 


Al . . . . 


C, Si . . 






Br, I . . 


Ca, Mg - 


Au . . • 


Pt • . . . 






H, Ag, . . 


Cd,Zn . . 
O • • . . 


Bo . . - . 








K, Na, ■ • 


Pb, Sn . . 




Pb, Sn . .. 




1 . . 


(NH 4 ), Li, 


S,Se. . 
Fe, Cr . . 

Mn, Co . 
Ni . • . • 


Fe, Cr . . 

Mn, Co . 

Ni ••• 

N, P .' 




N, P. 


S,Se. . . 






Bi, Sb, As. 




Bi, Sb, 


As. . . 


Cu.Hg. • 


Cu, Hg . 











The next table shows the valences, together with the 
symbols and formulae, of the most common electro-negative 
(acidulous) radicals: 

CI is the negative radical of all chlorides. 
Br is the negative radical of all bromides. 
I is the negative radical of all iodides. 
CN is the negative radical of all cyanides. 
HO is the negative radical of all hydrates. 
NOo is the negative radical of all nitrates. 
C10 3 is the negative radical of all chlorates. 
[ C 2 H 3 2 is the negative radical of all acetates (Ac.) 



M 1 



3 6 ESSENTIALS OF CHEMISTRY. 

O is the negative radical of all oxides. 
S is the negative, radical of all sulphides. 
S0 3 is the negative radical of all sulphites. 
* j S0 4 is the negative radical of all sulphates. 
C0 3 is the negative radical of all carbonates. 
C 2 4 is the negative radical of all oxalates (Ox.). 
C 4 H 4 6 is the negative radical of all tartrates (T.). 

%* f C 6 H 5 7 is the negative radical of all citrates (Cit). 
f-% \ P0 4 is the negative radical of all phosphates. 
Hf2 [ B 3 * s the ne S auve radical of all borates. 
FORMUL/E — In constructing formulas, (a) write the positive 
radical first and the negative second, thus: Ea CI; and (b) 
make their valences balance, thus: Ba Cl 2 ; for in every 
saturated compound each radical must possess the same 
number of valences. 

NOMENCLATURE — In naming a formula, give the simple 
name of the positive radical first, and then the name of the 
negative radical with the termination " -ide," if the nega- 
tive radical be an element, thus: 

Na 1 CI 1 Ca 11 Br x 2 
Sodium Chlor-ide; Calcium Brom-ide ; 

A\ m 2 O 3 Pt IV I 4 
Aluminum Ox-ide ; Platinum \od-ide. 

But if the negative be a compound radical, i.e., one in 
which another element, as oxygen, is associated with the 
leading negative element, the termination is " -tie " or " -ate" 
according to whether the negative element exercises its 
lower or higher valence, taking less or more oxygen, for 
example: 

NaCl0 2 NaC10 3 
Sodium Chlor-tfte; Sodium Chlor- ate ; 

If the negative element exercises a still lower or a still 
higher valence, and takes still less or still more oxygen? the 
prefix " hypo- " is used for the lowest and prefix i( per- " for 
the highest, thus ; 



PART I. — INORGANIC CHEMISTRY. 37 

Na CIO ; Na C10 2 
Sodium 7iypo<h\o-ite ; Sodium chlov-ite ; 

Na C10 3 ; Na CIO, 
Sodium chlor-tfte; Sodium p^r-chlor-ate. 

NOTE. — The student should refer to the tables of valences on the pre- 
ceding page, and practice combining positive radicals with negative ones 
until he can construct readily all the ordinary inorganic formula?. The 
teacher should persistently drill the class in this exercise, for its mastery 
removes one of the biggest of all bug-bears to the beginner in chemistry. 
It is best for the teacher to confine himself for the present to the simple 
system of nomenclature given above, ignoring confusing irregularities 
and exceptions, and obsolete synonyms, till he shall come to describe the 
various chemical substances themselves. 

II. The Chlorine Group. 



Name. 


Derivation of Name. 


Symbol. 


At. Wt. 


Fluorine, 


Fluor spar, 


F, 


19 


Chlorine, 


j/.w/3oc, green, 


CI, 


35-5 


Bromine, 


iSptiuGc, stink, 


Br, 


80 


Iodine, 


Iwffyf> violet, 


I, 


127 



The members of this group are all univalent and much alike in 



Fig. 16. 



m 



their sources and physical and chemical properties. They differ 
in degree rather than in kind, forming a graded series. Hence 
we will consider them all together. 



38 ESSENTIALS OF CHEMISTRY. 

Sources. — Never free in nature. The principal source of fluor- 
ine is fluor spar (CaF 2 ), while compounds of chlorine, bromine 
and iodine occur in sea and other salt waters. 

Preparation. — Free fluorine is obtained only with great diffi- 
culty ; the others may be prepared by removing the hydrogen 
from their hydrogen salts (hydracids) by means of oxygen derived 
from manganese dioxide, 37 thus : — 

4HCI + Mn0 2 = MnCl 2 + 2H 2 + Cl 2 . 
4HBr + Mn0 2 = MnBr 2 -f 2H 2 -f Br 2 . 
4HI + MnO a == Mnl 2 +2H 2 + I 2 . 38 

Physical Properties. — Fluorine is a nearly colorless gas, with 
properties resembling chlorine, but more intense. Chlorine is a 
very irritating yellowish-green gas, two and a half times as heavy 
as air, slightly soluble in water (three volumes), forming "Aqua 
chlori, U. S. P." Bromine is a red liquid, giving off red vapors of 
a disagreeable, irritating odor; very slightly soluble in water. 

Iodine is a solid, in bluish-gray scales, which, when warmed, 
give off violet vapors ; practically insoluble in water except by the 
intervention of an alkaline iodide ; 42 soluble in alcohol ; irritating, 
even caustic. 

Chemical Properties. — Intensely electro-negative ; great affinity 
for the metals, 40 especially hydrogen. 41 In negativeness, and con- 
Experiments 40 and 41 had best be performed by the instructor. 

37 Into a flask standing in a dish of water warmed over a heater and the 
whole apparatus (Fig. 16) under a hood, pour several ounces of HC1 and half 
as much Mn0 2 in lumps, and agitate. The gas passes out, and being heavier 
than air, collects in the bottle, where its yellowish green color makes it visible. 

38 To each of three small test-tubes add a few grains of manganese dioxide. 
To the first add a few crystals of Na CI, to the second, of K Br, and to the third, 
of K I. Add a few drops of strong H. 2 S0 4 and warm. Note the evolution of 
CI from the first, Br from the second, and I from the third, and study the prop- 
erties of each, taking care not to inhale them, and stopping the reaction as 
soon as the test is finished. 

* 9 To a little chlorinated lime (bleaching powder) in a test-tube, add some 
dilute acid and note the evolution of CI. 

40 Into a jar of chlorine introduce some copper or bronze foil, or sprinkle 
some powdered antimony. They inflame spontaneously. 

41 (a) Into a jar of chlorine lower a lighted candle. The hydrogen of the 



PART I. INORGANIC CHEMISTRY. 39 

sequently in affinity for the metals, F is greatest, CI next, Br next, 
and I least. Therefore, in compounds with the metals, F will 
displace CI, and CI will displace Br, and either F, CI, or Br will 
displace I. 42 These elements destroy coloring matters and noxi- 
ous effluvia in two ways : (i) by abstracting their hydrogen; (2) 
by abstracting the hydrogen of water, setting free nascent oxygen, 
which oxidizes the matters in question. 43 

Medical. — Chlorine gas and bromine vapor are used for disin- 
fection. Inhaled they cause severe coryza and bronchitis. Taken 
into the stomach, bromine and iodine cause gastro-enteritis. The 
antidote is boiled starch. Locally bromine is used as an escha- 
rotic and iodine as a counter-irritant. 

Pharmaceutical. — The following preparations are officinal : 
Tinctura Iodi (7 per cent.) ; and Liquor Jodi Compositus (Lugol's 
Solution) (Iodine 5, potassium iodide to, and water 100). The 
so-called colorless tincture of iodine is made by adding ammonia- 
water to the tincture until it is decolorized by converting the 
iodine into ammonium iodide. 44 

tallow burns in the chlorine to form hydrochloric acid, and all the carbon is 
liberated as smoke. {&) Into a similar jar thrust a piece of paper dipped in 
warm turpentine. It inflames spontaneously and burns, evolving dense clouds 
of smoke. 

42 Take two large test-tubes half full of water. Into one put a grain of po- 
tassium bromide, into the other potassium iodide; add chlorine-water to each. 
The chlorine will liberate the bromine in one and the iodine in the other. This 
may be shown (a) by their color; (&) by adding a few drops of carbon bisul- 
phide or chloroform, which on agitation will gather all the free bromine and 
iodine, and be colored brown with the one and violet with the other; or (c) 
by adding a few drops of starch -water, which will give brown with bromine 
and a deep blue with iodine. 

43 (a) Into one bottle of chlorine gas introduce a piece of dry calico, into 
another a moist piece. The moist calico is rapidly bleached, while the dry is 
but slowly affected. (£) To a solution of indigo, cochineal, or some aniline 
color, add chlorine water. It is immediately decolorized. 

44 Put a crystal of iodine in each of three small test-tubes, to the first add 
some water, to the second, alcohol, and to the third, a solution of potassium 
iodide; note it is very slightly soluble in water but readily so in alcohol and 
in a solution of potassium iodide. Put a drop of the alcohol solution (tincture) 
on the hand and note the brown stain. To each of the test-tubes add a few 
drops of ammonia water or liquor potassae and note the disappearance of the 
brown color. 



40 ESSENTIALS OF CHEMISTRY. 

Tests. — In the free state chlorine and bromine may be known 
by their bleaching, color, odor, etc. Iodine is recognized by the 
blue color it strikes with starch. 

ACIDS. — Just as in the world at large, the balancing of 
forces is due to a general struggle between opposite and 
antagonistic qualities, as between light and darkness, heat 
and cold; so the chemical status seems to be a resultant of 
the antagonism of the opposing " positive " and " negative " 
within the molecule. If the positive radical predominates 
over the negative, this excess of positiveness gives the com- 
pound an alkaline character ; while on the other hand a 
predominance of the negative over the positive gives it an 
acid character. Thus an excess of negativeness or of 
positiveness finds expression in the compound as acidity 45 or 
alkalinity. 46 

Since H is the weakest of all positive radicals, it is over it 
that strong negative radicals predominate most completely ; 
so that the hydrogen salts are as a class the most acid 47 in 
all chemistry, in fact they are called the acids. 

Acids may be divided into two classes: 

(a) Hydracids which are the " -ide " salts of hydrogen, the 
negative radicals consisting only of a single element. 

(J>) Oxacids in which the negative element has oxygen 
associated with it, forming a compound negative radical. 
The acids are given a somewhat special nomenclature, the 
main portion of which is derived from the name of the 



45 Acid substances may be recognized by their usually having a sour 
taste, by redding certain vegetable coloring matters, such as litmus, and 
by neutralizing alkalies. 

46 Alkaline substances generally have a soapy taste and neutralize 
acids, and restore to the original color vegetable matters reddened by 
acids. 

47 Hydrogen hydrate (HHO) or water is one salt of hydrogen that is 
not acid. The radical HO being as weakly negative as H is weakly 
Dosltive, neither predominates, and water is neutral. 



PART I. INORGANIC CHEMISTRY. 4 1 

negative element. Hydracids are given the prefix " hydro- " 
and the termination "-ic." The oxacids conform to the 
regular nomenclature except that the word "acid " is used 
instead of the name of the positive radical, hydrogen, and 
the terminations "-ate" and " -ite " become " -ic " and 
"-ous" respectively. These rules are illustrated in the 
little table of chlorine acids given below. The oxacids are 
generally considered as formed by the combination of water 
with the oxides of the negative element, the different oxides 
being distinguished by prefixes' derived from the Greek 
numerals indicating the number of oxygen atoms, thus: 

CI 2 0— Chlorine Monoxide. 
C1 2 2 (?)— Chlorine Dioxide. 
C1 2 3 — Chlorine Trioxide. 
C1 2 4 — Chlorine Tetroxide. 
2 5 — Chlorine Pentoxide. 
C1 2 7 — Chlorine Heptoxide. 

The following table illustrates the formation and nomen- 
clature of the chlorine acids: 

Cl a O+H 2 0— 2HCIG — Hydrogen Hypochlorite— Hypochlorous acid. 
Cl 2 3 -r-H 2 0=2HC10 2 — Hydrogen Chlorite— Chlorous acid. 
Cl 2 5 -hH 2 0— 2HOO a — Hydrogen Chlorate— Chloric acid. 
Cl 2 7 -f H 2 0=2HC10 4 — Hydrogen Perchlorate— Perchloric acid. 

The Hydracids of the chlorine group are as follows : — 

H + F = II F — Hydrogen Fluoride — Hydrofluoric acid. 

H + CI = HC1 — Hydrogen Chloride — Hydrochloric (muriatic) acid. 

H-f Br — HBr — Hydrogen Bromide — Hydrobromic acid. 

H -j- I — HI — Hydrogen Iodide — Hydriodic acid. 

Prepared by treating the appropriate salt with H 2 S0 4 , thus : — 

CaF, + H 2 S0 4 = CaS0 4 + 2HF. 
2NaCl + H~S0 4 = Na 2 S0 4 + 2HCI.* 8 
2KBr + H 2 S0 4 = K 2 S0 4 + 2HBr. 
2KI + H 2 S0 4 = K 2 S0 4 + 2HI. 

48 To prepare hydrochloric acid gas, put several ounces of common salt and 
4 



42 



ESSENTIALS OF CHEMISTRY. 



Physical Properties. — Colorless, irritating gases; sharp, sour 
taste ; 49 very soluble, water dissolving several hundred times its 
own volume, forming aquae known by the simple name of the acid 
itself, thus : The officinal " hydrochloric acid " is a solution of the 
hydrochloric acid gas in water. 

Fig. 17. 




Chemical Properties. — Strong acids ; true acids even without 
water. 

Uses. — HF attacks silica energetically, hence is used to etch 
glass ; very poisonous, and burns made by it heal with difficulty. 

about twice as much sulphuric acid into a flask, and warm. The gas comes off 
in abundance and may be collected in a dry bottle (like chlorine, Fig. 16), or 
over mercury. The solution of the gas (the ordinary form) is obtained by 
passing the gas through a series of Wolff bottles containing cold water and 
arranged as shown in Fig. 17. For making HBr or III, phosphoric acid is 
better, since sulphuric is apt to be partially reduced with evolution of S0 2 . 

49 Fill a large dry glass tube with HC1 gas and quickly invert it in a dish of 
water colored blue with litmus. Note that the gas is instantly dissolved and 
that the water rushes up to take its place and the litmus is reddened by 
the acid. Let some of the gas pour into the mouth and note sour taste. 



PART I. — INORGANIC CHEMISTRY. 43 

HCl is very useful in the arts. Aqua regia, or nitro-muriatic 
acid, is a mixture of nitric and hydrochloric acids. It is the 
best solvent of gold 50 and platinum. The metals are attacked 
by the nascent chlorine which is evolved when the H of the HCl 
is oxidized by the O of the HNO a . In medicine HCl is often 
prescribed as a tonic. 

HBr, like all bromides, is a sedative. HI, like all iodides, is 
an alterative. 

Tests.— Fluoride - H 2 S0 4 — etches glass. 51 - 52 

Chloride -fAgN0 3 — white precipitate, soluble in ammonia. 

Bromide + AgNO a — yellowish-white precipitate, slightly soluble 
in ammonia. 

Iodide + AgN0 3 — yellow precipitate, insoluble in ammonia. 53 

If to a bromide or iodide some chlorine-water and starch paste 
be added, the bromine and iodine will be liberated, the bromine 
striking a brown and the iodine a blue color with the starch. 

Oxysai.ts of the Chlorine Group. — The members of the chlorine 
group are so electro-negative that they have but little affinity for 
oxygen, it being also strongly electro-negative. Bromine has for 



50 Take two beakers and put into one 5 Cc. of HCl and into the other 2 Cc. 
of HNO3. Add to each a sheet of gold-leaf. Note that the gold-leaf is un- 
affected. Now pour the contents of one beaker into the other and note that 
the gold-leaf is dissolved in the mixed acids (aqua regia). 

51 On a plate of glass coated with wax or copper- plate varnish (six parts of 
mastic, one of asphalt, and one of wax dissolved in turpentine) draw a design 
with a pointed instrument. Invert over a lead dish containing pow T dered 
CaF. 2 moistened with strong H 2 S0 4 and warm gently. Hydrofluoric acid gas 
is evolved and attacks the glass wherever the wax has been scratched off. 
Upon removing the wax the design is found permanently etched on the glass. 

52 To a small lead dish about the size of a watch crystal, such as any tinner 
can stamp out of sheet lead, add 5 grains of CaF. 2 and moisten with strong 
H 2 S0 4 . Cover this with a watch crystal coated with melted paraffin and on 
which the student has drawn a design with a needle or fine pencil point, and 
warm gently. Leave during lecture hour and note the etching. 

53 Take three small test-tubes and add a few drops of a solution of a chloride 
to the first, of a bromide to the second, and of an iodide to the third. Add to 
each 5 drops of AgNQ, solution. Note a pure white precipitate of AgCl in 
the first, a yellowish white of AgBr in the second, and a yellow of Agl in the 
third. Add ammonia water to each and note that the AgCl dissolves easily, 
the AgBr with difficulty, and the Agl remains insoluble. 



44 ESSENTIALS OF CHEMISTRY. 

it less affinity than iodine, chlorine less than bromine, and fluorine 
so little that it never combines with oxygen at all. Hence the 
oxysalts of the group are very unstable substances, decomposing 
easily, and readily giving up their oxygen. So they are much 
used in chemistry as oxidizing agents, 54 in medicine as disin- 
fectants, and in the combustible and explosive mixtures of pyro- 
techny, etc. 55 

III. Sulphur Group. 

Oxygen (already described) O • 16 

Sulphur S 32 

Selenium Se 79 

Tellurium Te 128 

The elements comprising this group are solid at ordinary tem- 
peratures ; bivalent and sexivalent ;. possess electro-negative 
affinities which, as in most other groups, decrease as the atomic 
weights increase ; form hydracids as well as oxacids. 

The analogy between their compounds is shown in the follow- 
ing table : 

Hydro-ic Hypo-ous 



Acid. 


Dioxide. 


Trioxide. 


Acid. 


-ous Acid. 


-ic Acid. 


H 2 S 


so, 


so 3 


H 2 S0 2 


H 2 S0 3 


H 2 S0 4 . 


H 2 Se 


Se0. 2 


Se0 3 




H 2 Se0 3 


H 2 Se0 4 . 


H 2 Te 


Te0 2 


Te0 3 




H 2 Te0 3 


H 2 Te0 4 



Selenium and Tellurium are of no medical interest, and will not 
be noticed further. 



5 * Their oxidizing action on combustibles maybe shown by: (a) Mix to- 
gether a drachm each of powdered potassium chlorate and sugar; place on a 
brick, and touch off with a glass rod dipped in sulphuric acid. A vigorous 
combustion occurs, (b) Drop some crystals of potassium chlorate into a con- 
ical glass of water; add several bits of phosphorus; then by means of a pipette 
introduce sulphuric acid at the bottom of the glass. The phosphorus takes 
fire and burns at the expense of the oxygen of the potassium chlorate. 

55 Mix on a sheet of paper 2 grams of powdered potassium chlorate and .5 
gram of some combustible powder, as sulphur, antimony sulphide, oj tannin. 
Wrap it up in the paper, place upon an anvil, and strike with ahammer. It 
explodes violently. 



PART I. INORGANIC CHEMISTRY. 



45 



SULPHUR occurs free, especially in the neighborhood of vol- 
canoes ; occurs combined as sulphides and sulphates in many 
valuable ores, and in small quantity in the animal and vegetable 
kingdoms. 

Preparation, — The native sulphur, freed from stones, is refined 
by distillation, as shown in Fig. 18. The crude sulphur is melted 
in the tank by the hot draft from the fire below, and then runs 
down through a pipe into the retort, where it is vaporized. This 

Fig. 18. 




vapor, entering a large brick chamber, is condensed into fine, 
feathery crystals, called flowers of sulphur or sublimed sulphur. 
If the chamber be hot, it condenses into a liquid, which is drawn 
off and moulded into rolls, called roll brimstone. Sublimed sul- 
phur is apt to contain more or less acid, and is washed (sulphur 
lotum). Boiled with lime and precipitated with HC1, it forms 
sulphur precipitatum, U. S. P. This mixed with water is milk of 
sulphur (lac sulphuris, U. S. P.). 



46 ESSENTIALS OF CHEMISTRY. 

Physical Properties, A brittle yellow solid ; insoluble in water, 
hence tasteless; almost insoluble in alcohol, but very soluble in 
benzine, chloroform and carbon disulphide. It occurs in four 
allotropic modifications. 56 

Chemical Properties. — Inflammable, hence called "brimstone" 
(burn-stone). Combines with metals, 57 forming sulphides. 58 Sul- 
phur forms compounds remarkably analogous to those of oxygen, 

'. £••• — 

H 2 , . .KHO C0 2 H 2 C0 3 HCNO. 

H 2 S KHS CS 2 H 2 CS 3 HCNS. 

Uses. — In the arts, to make gunpowder, matches, etc. ; in med- 
icine, as a laxative, parasiticide and alterative. We have only 
theoretical explanations of the method of its absorption ; but that 
it is absorbed is certain, for persons taking it excrete enough to 
blacken silver carried on the person. 

Hydrogen Sulphide — H 2 S — Hydro sulphuric Acid or Sulphur- 
etted Hydrogen — occurs in sewer gas and other effluvia from de- 
composing organic sulphurized matters, and in the water of sul- 
phur springs. 

Prepared in laboratory by decomposing a sulphide, 59 thus : — 

FeS -f H 2 S0 4 = FeS0 4 + H 2 S. 



56 Melt a tablespoonful of sulphur in a covered porcelain dish or crucible; 
let it cool and break the crust that forms and pour the still melted sulphur into 
water. Note (a) the prisms remaining in the dish as well as (b) the plastic 
amorpkoussulphm in the water. Dissolve a pinch of sulphur in a few drops of 
CS 2 ; allow a drop to evaporate on a slide and examine (c) the rhombic crys- 
tals under the microscope. Boil a little lime and sulphur in water; decant the 
clear liquid and add HC1. Note the (d) amorphous white powder of precipi- 
tated sulphur suspended in the liquid (milk of sulphur). 

57 In a small glass flask, a little sulphur is heated to boiling. If now a bun- 
dle of fine copper wire or a piece of sodium, in a combustion spoon, be previ- 
ously heated and then lowered into the vapor, it burns brilliantly. 

58 Mix in a dish equal parts of iron filings and flowers of sulphur.: moisten 
with water and set aside. Within a half hour it gets hot, vaporizes the water, 
and is converted into a black mass of FeS. 

59 Into a side-neck test-tube, or better a flask with funnel and delivery tube, 
Fig. 19, put a few lumps of FeS and dilute H 2 S0 4 or HC1 enough to cover the 
FeS. Note the physical and chemical properties of the gas evolved. 



PART I. INORGANIC CHEMISTRY. 



47 



Physical Properties. — Colorless gas, having the odor of rotten 
eggs or intestinal flatus ; slightly soluble in water. 

Chemical Properties, — Very feeble acid : burns 60 with pale blue 
flame : — 

H 2 S + 30 = S0 2 + H 2 0. 

Forms characteristic precipitates with most metallic salts, 61 hence 
a valuable test reagent. 

Fig. 19. 




Tests. — The presence of H 2 S even in minute quantities may be 



*" ;0 Burn the gas from a jet : (a) Hold near the flame a glass rod dipped in 
ammonia; white crystals of ammonium sulphite are formed, (b) Hold a cold, 
dry bell-glass over the flame; it is bedewed with water. 

61 To show the action of H 2 S on metallic salts, connect several wash bottles 
with the generator as shown in Fig. 20. A dilute solution of lead acetate is 
put in the first, of tartar emetic (antimony) in the second, of arsenic in the 
third, of zinc sulphate in the fourth. The gas in passing precipitates lead sul- 
phide (black) in the first, antimonicus sulphide (orange) in the second, arsen- 
ous sulphide (yellow) in the third, zinc sulphide (white) in the fourth. 



4« 



ESSENTIALS OF CHEMISTRY. 



detected by its odor, and by its blackening paper moistened with 
a solution of lead acetate. 



Fig. 20. 




Physiological. — When inhaled, H 2 S is an active poison, combin- 
ing with the hsemgalobulin and destroying its oxygen-carrying 
power. Even when highly diluted, as in the atmosphere of city 
dwellings, clumsily "fitted with the modern conveniences," it pro- 
duces a low febrile condition. When concentrated, or even mod- 
erately diluted (one per cent, and over), the gas proves rapidly 
fatal. 

Treatment. — Fresh air, artificial respiration, and stimulation. 

Carbon Bisulphide — CS 2 . — Obtained by bringing S into con- 
tact with heated charcoal. A colorless, volatile liquid of a fetid 
odor, unless it is very pure. A valuable solvent for S, P, india- 
rubber, etc. Dissolved in water (1-400) a useful antiseptic. 

Sulphur Oxides and Acids. 

Dioxide — S0 2 +H 2 0==H 2 S0 3 — Sulphurous acid. 
Trioxide — S0 3 -|-H 2 0— H 2 S0 4 — Sulphuric acid. 



PART I. INORGANIC CHEMISTRY. 49 

Sulphur Dioxide, S0 2 , occurs whenever sulphur or any of its 
compounds are burned in air or oxygen. 

Prepared in laboratory by decomposing and reducing sulphuric 
acid by copper or charcoal, 62 thus : 

2H 2 S0 4 +Cu=CuS0 4 +2H. 2 0+S0 2 . 
2H 2 S0 4 + C =2S0 2 +C0 2 +2H 2 0. 

Physical Properties, — A colorless gas, with a suffocating odor 
(of burning matches) ; dissolves in water to form sulphurous acid 
(H 2 S0 3 ). 

Chemical Properties. — Neither burns nor supports combustion; 
a strong deoxidizer ; by removing O from coloring matters and 
infecting germs it bleaches 63 and disinfects. 

Uses.— Sulphur dioxide, sulphurous acid, and the sulphites 
possess the property of destroying microorganisms and arresting 
fermentations. A sulphite digested with sulphur forms a so-called 
hyposulphite, thus : 

Na,S0 3 +S-=Na 2 S 2 3 . 

Sodium hyposulphite, more correctly called sodium thiosul- 
phate, has the same uses as the sulphites, and is also a valuable 
solvent of the silver salts in photography. 

Sulphur Trioxide, S0 3 . — Made by oxidizing S0 2 in the manu- 
facture of sulphuric acid. This is done upon a large scale by 
passing S0 2 from burning sulphur into a chamber kept filled with 

62 To make S0. 2 and study its properties: (a) burn a sulphur match; (b) 
warm a mixture of powdered S and H.,S0 4 ; (c) heat copper wire in strong 
H. 2 S0 4 ; (d) add HC1 to sodium sulphite. Note that the gas is colorless and 
irrespirable, neither burns nor supports combustion, dissolves in water, form- 
ing an acid solution (H 2 S0 3 ) that tastes sour and bleaches organic colors. 

63 Some sulphur is ignited beneath a tripod on which fresh flowers are 
placed, and the whole covered by a bell-glass. The flowers are bleached. 
The color may be restored by washing with some dilute alkali or acid that will 
combine with or displace the S0 2 , or with very dilute nitric acid, which will 
restore the oxygen removed by the S0 2 . 



50 ESSENTIALS OF CHEMISTRY. 

vapor of nitric acid, steam and air. 64 The nitric acid gives up a 
part of its oxygen to oxidize a portion of the S0 2 to S0 3 . 

2HN0» + 3S0 2 1=± 3SO3 + II 2 + N 2 2 . 

The S0 3 then combines with the water thus produced (S0 8 + 
H 2 0==H 2 S0 4 ), and more water is supplied by a jet of steam 
thrown constantly into the chamber. 

The N 2 2 has the power of taking up oxygen from the air and 
becoming N 2 4 , 

N 2 2 + 2 = N 2 4 , 

which in turn parts with this oxygen to oxidize a new quantity 
of S0 2 , 

N 2 4 + 2S0 2 = N 2 2 + 2SO a . 

Thus the process is kept up as long as the S0 2 , air, steam, and 
N 2 2 are supplied. The acid condenses with the water upon the 
floor of the chamber, and is drawn off, concentrated, and sold as 

Sulphuric Acid— H 2 SQ — " Oil of Vitriol." 65 

Physical Properties. — A dense, colorless, oily-looking liquid, 
without odor. 66 

Chemical Properties. — Strong acid ; very avid of water, not 
only dissolving in it, but combining with it, the act evolving con- 
siderable heat ; 67 chars organic matters by abstracting H and O 
to form water. 68 



61 The manufacture of sulphuric acid may be illustrated on the lecture table 
by the apparatus shown in Fig. 21. The lead chamber is represented by a 
large flask. Into this are led (a) N 2 2 from the flask on the right; (b) S0 2 
from a mixture of sulphur and manganese dioxide in the flask in the rear; (c) 
steam from the other flask, and (d) air or oxygen through the open tubes. 

65 To make H 2 S0 4 in small test-tubes, (a) Boil a little powdered sulphur 
and strong HN0 8 ; (£) carefully heat a pinch of sulphur with a few crystals of 
KC10 ;H till it ignites; test for H 2 S0 4 by means of BaCl 2 solution. 

66 Take a reagent bottle of strong H 2 S0 4 and note its appearance, weight, 
taste, etc. 

67 To about 5 Cc. of it in a test-tube add an equal bulk of water and note 
heat produced. 

6S Moisten a bit of match, paper, cloth or other organic substance, with the 
acid and note that it is charred, even the dilute acid doing so if it is warmed; 
and for this reason be careful not to spill any on the table or your clothes. 



PART I. INORGANIC CHEMISTRY. 



Si 



Tests. — (i) The concentrated acid, if placed on a piece of 
paper or other organic material, will char it. fi9 If dilute, it will 
char the paper only after being warmed and concentrated by the 



Fig. 21. 




evaporation of its water. (2) Sulphuric acid, or any other sul- 
phate, will form with a solution of a barium salt a white precipi- 
tate (BaS0 4 ) insoluble in nitric or hydrochloric acid. 70 

Uses. — So important in the arts that the commercial prosperity 
of a country may be measured by the amount of H. 2 S0 4 con- 
sumed. Properly diluted, it is a refrigerant tonic, but concen 
trated it is a severe caustic. 



69 Pour some strong H.,S0 4 on an equal quantity of sugar or strong syrup ; 
note that a mass of charcoal is formed. 

10 To 5 Cc. of water in a test-tube add a few drops of some sulphate and 
then a few drops of BaCl 2 . Note white precipitate. Agitate and pour half 
into another tube. Add HC1 to the 6rst tube and HN0 3 to second, and note 
that the precipitate (BaS0 4 ) is not dissolved. 



52 ESSENTIALS OF CHEMISTRY. 

IV. Nitrogen Group. 

Nitrogen, N 14 

Phosphorus, P 31 

Arsenic, As 75 

Antimony (Stibium), Sb 120 

Bismuth, . Bi 208 

Trivalent and Quinquivalent. This group, as shown below, 
forms a graded series from nitrogen at the negative, to bismuth 
at the positive end : — 

N P As Sb < Bi 

14 31 75 120 208 

Sp. gr. 1.83. Sp. gr. 5.67. Sp. gr. 6.7. Sp. gr. 9.8. 
Gas, with full A soft solid. Solid. Dense solid. Very dense solid, 
negative ten- 
dencies. Easily volatiliz- Volatilizable. Difficultly vola- Non-volatil- 
able. tilizable. izable. 
Destitute of me- Some metallic Great metallic Full metallic lus- 

tallic lustre. lustre. lustre. tre. 
Negative ten- Both negative More positive Full positive ten- 
dencies, and positive tendencies. dencies. 
tendencies. 

The following will exhibit the relations of some of the most 
important compounds : — 

Hydrides. Chlorides. Oxides. Sulphides. 

-otis. -ic. -ous. -z'c. -ous. -ic. 

NH 3 NCI3, .... N 2 3 , N 2 5 

PH 3 PCI3, PC1 5 P 2 3 , P 2 6 P 2 S 3 , P 2 S 5 

AsH 3 AsCl 3 , AsCl 5 As 2 3 , As 2 5 As 2 S 3 , As 2 S 5 

SbH 3 SbCl 3 , SbCl 5 Sb,0 3 , Sb 2 5 Sb 2 S 3 , Sb 2 S 5 

BiCl 3 Bi 2 3 , Bi 2 5 Bi 2 S 3 .... 

Vanadium, Columbium and Tantalum belong to this group, 
but are rare metals and as yet of little importance. 

NITROGEN occurs uncombined in the atmosphere ; com- 
bined in some mineral, and all vegetable and animal bodies, 
especially in the more highly organized tissues. 

Prepared most easily by burning phosphorus in a confined 



PART I. — INORGANIC CHEMISTRY. 



53 



space until the oxygen is removed from the air. 71 Prepared in 
this way it contains small quantities of other gases found in air. 
To prepare it pure, heat ammonium nitrite (NH 4 N0 2 = 
2 H,Oi-N 2 ). 

Physical Properties. — A colorless, tasteless, odorless gas, a little 
lighter than air. 

Chemical Properties. — Little tendency to combine with other 
elements, and its compounds, once formed, are very prone to 

Fig. 22. 




decompose, either with violent decomposition 72 or gradual putre- 
faction ; neither combustible nor a supporter of combustion ; 
negatively poisonous. 

The Atmosphere. Air, considered by the ancients one of 
the four elements (fire, earth, air and water), is neither an ele- 
ment nor a compound. It is a mixture, 73 mainly of nitrogen and 



71 A flat piece of cork floating on water supports a capsule containing a bit 
of phosphorus carefully dried. This is ignited and immediately covered with 
a bell jar. The jar is filled with a dense white cloud from the combustion, 
which ceases only when the oxygen is all consumed. At first the air expands, 
and some may be forced out. Upon cooling, the water rises to take the place 
of the oxygen, the white fumes gradually dissolve in the water, and the 
nitrogen is left clear and comparatively pure, Fig. 22. 

12 To tincture of iodine add excess of ammonia water. Filter to separate 
the precipitated iodide of nitrogen. Put portions of this on separate bits of 
paper and set aside. When dry they explode on the slightest touch. 

73 Proofs that air is a mixture: (i) Its constituents are not in atomic pro- 



54 ESSENTIALS OF CHEMISTRY. 

oxygen, the function of the former being to dilute the latter. Mil- 
ler gives the average composition of air as follows : 

Volumes. 

Nitrogen °. 77-95 

Oxygen 20.61 

Carbon dioxide * 03 

Aqueous vapor 1 .40 

Also traces of nitric acid, ammonia, sodium chloride, ozone, 
dust, bacteria, germs, etc. In the neighborhood of large cities 
various other substances are poured into the air from manufactor- 
ies. Yet, owing to the rapid diffusion of gases, the composition 
of the air is almost the same everywhere. 

Watery Vapor, The higher the temperature the more water 
air will hold. A warm, dry, air, when cooled, will appear damp, 
and the temperature at which it begins to deposit its water is its 
dew point. A cold, damp air, when heated, becomes capable of 
holding more water, and appears dry, hence the necessity of sup- 
plying water to the heated air of our rooms in winter, especially 
in cases of bronchitis or catarrhal croup. Even in health, a very 
dry air irritates the air passages, produces dryness of the skin and 
malaise ; while a very moist atmosphere retards evaporation from 
the skin and lungs, raises the body temperature and becomes 
oppressive. 

Suspended Matters in air are of a great variety of substances. 
The irritation of dust incident to certain trades may cause chronic 
bronchitis, emphysema and phthisis. Germs floating in the air 
are believed to be the cause of many contagious, infectious, and 
malarial diseases. The best disinfectants 74 are (a) free ventila- 

portions; (2) air can be. made by mechanically mixing the gases; (3) sol- 
vents may remove one gas without affecting the others, each dissolving accord- 
ing to its own solubility. 

14: Disinfectants destroy the power to infect, whether it be due to germs or 
other agents. 

Germicides destroy germs. 
Antiseptics prevent putrefaction. 
Antizymotics prevent fermentation. 
Deodorizers destroy offensive odors. 



PART I. — INORGANIC CHEMISTRY. 55 

tion and consequent dilution ; (b) chlorine, bromine, iodine and 
formaldehyde, sulphur dioxide and formaldehyde. 

Argon, Helium, &c. Argon was discovered in 1894 by Lord 
Rayleigh and Prof. Ramsay, as a residue (1 per cent.) after 
removing all the oxygen, nitrogen, etc., from air. A colorless, 
odorless gas that out-nitrogens nitrogen in its lack of affinity. 
Helium, (yfaog, the sun) has, from its line in the solar spectrum, 
long been known to exist in the sun's atmosphere, but was not 
discovered till 1895, when Ramsay obtained it from certain 
minerals. Krypton and Neon are two new elements Ramsay and 
Travers claim to have recently discovered. 

AMMONIA, NH 3 . — Occurs in the effluvia from decomposing 
nitrogenized organic bodies ; for nitrogen, and hydrogen will not 
combine except in the nascent state (see page 33). First 
obtained from the destructive distillation of camels' dung near the 
temple of Jupiter-Ammon in Libya; hence called " ammonia." 
Later it was obtained by heating clippings of hides, hoofs and 
horns, 75 especially of deer (the hart) in closed iron retorts, and 
was called " spirit of hartshorn." Coal contains about two per 
cent, of nitrogen, a part of which in the manufacture (destructive 
distillation) of coal-gas comes off as ammonia. In washing the 
coal-gas the ammonia dissolves, and this solution is now its com- 
mercial source. 

Preparation. — Ammonia may be prepared in various ways, as 
above suggested. In the laboratory it is usually obtained by driv- 
ing it off from the commercial "aqua ammoniee " by heat. 

Physical Properties. — Transparent, colorless gas of an irritating 
odor ; condenses under a pressure of about 100 pounds to square 
inch (6 or 7 atmospheres) at ordinaiy temperatures, into a color- 



75 Mix some Ca2HO, KHO or XaHO with some nitrogenized organic sub- 
stance, as albumin, wool or, best of all, and easily obtainable and agreeable, 
chipped dried-beef. Heat in a test-tube. Ammonia gas is evolved, recog- 
nized by its odor, alkalinity, or by white fumes when a glass rod is thrust into 
the mouth of the tube. 



56 



ESSENTIALS OF CHEMISTRY. 



less liquid. 76 Ammonia is exceedingly soluble, water dissolving 
from 500 to 1000 times its own volume. 77 

Chemical Properties. — Ammonia is not ordinarily combustible, 
though it may be made to burn if mixed with a small amount of 
oxygen. It is alkaline in solution, and combines with acids to 



Fig. 24. 



Fig. 23. 





form the well-known ammonium salts which will be considered in 
another group. 

Uses. — Ammonia, liquefied in iron drums strong enough to 
resist the pressure, is sold in large quantities for ice-making. 
Water of ammonia is largely employed in chemistry, pharmacy 
and medicine, the gas from it being often administered in syn- 
cope, chloroform narcosis, etc., but care must be taken lest its too 



76 Make ammonium-silver chloride by passing ammonia gas over silver 
chloride. Seal this in a bent glass tube (Fig. 23). The end containing the 
compound is heated in a water-bath, while the other is cooled in an ice 
mixture. Ammonia gas is driven off from the compound, and condenses into 
a colorless liquid in the cold end of the tube. 

77 The absorption of ammonia gas by water may be illustrated by filling a 
large bottle with the gas by upward displacement, and closing the mouth 
with a rubber cork through which passes a glass tube sealed at its outer end. If 
this sealed end be plunged under water and broken off, the water rushes in 
forming a beautiful fountain (Fig. 24). If the water be colored red with 
litmus, it will become blue as it enters the bottle, showing that the water has 
become alkaline. 



PART I. — INORGANIC CHEMISTRY. 



57 



liberal use on the unconscious patient cause spasm of the glottis 
or set up a dangerous bronchitis. 

Tests, — The gas may be recognized by (a) its smell, (/£) white 
fumes with HO, (c) turning moistened red litmus blue. Its 
compounds must be warmed with a strong alkali 78 to liberate the 
ammonia gas, which can then be recognized as just described. A 
most delicate test is Nessler's Reagent, 79 which gives a yellowish 
brown with ammonia or its compounds. 

Fig. 25. 




Nitrogen Oxides. 



M onoxide — N 2 + H 2 = 2HNO = Hyponitrous acid. 
Dioxide — N 2 2 . No corresponding acid. 
Trioxide— N 2 3 + H 2 =■ 2HN0 2 = Nitrous acid. 
Tetroxide — N 2 4 . No corresponding acid. 
Pentoxide— N 2 5 -f H 2 = 2HNO3 = Nitric acid - 



78 Mix lime with NH 4 C1 and heat in a test-tube. Test the NH 3 as above de- 
scribed, and expose to it a paper moistened with CuS0 4 solution, and note the 
deep blue ammonio -sulphate of copper formed. 

79 Nessler's Reagent. Dissolve 35 gm. of Kl in 100 Cc. of water and 17 gm. 
of HgQ 2 in 300 Cc. of water; add the first to the second until the precipitate 
first formed is almost re-dissolved. Then add 20 per cent. NaHO solution, 
enough to make one liter. 



58 ESSENTIALS OF CHEMISTRY. 

Nitrogen Monoxide — N 2 {Nitrous Oxide — Laughing Gas), 
— Prepared by heating ammonium nitrate, 80 as shown in Fig. 25. 

NH 4 N0 8 = N 2 + 2H 2 0. 

Physical Properties. — Colorless, odorless gas, of sweetish taste. 
Dentists keep it liquefied under pressure in iron cylinders. 

Chemical Properties. — By the ease with which it gives up its O 
it is a supporter of combustion and life, next to O itself. 

Medical. — Inhaled, diluted with air, it produces exhilaration of 
spirits, muscular activity, and then complete anaesthesia. Used in 
dental and other brief minor operations. 

Nitrogen Dioxide — N 2 2 {Nitric Oxide). — Prepared by action 
of nitric acid on copper : — S1 

3C11 + 8HNO3 = 3Cu(N0 3 ) 2/ f- 4H 2 + N 2 2 . 

A colorless gas, which, when coming in contact with free O, forms 
red vapors of N 2 8 and N 2 4 ; hence a test for free O. Unlike 
N 2 0, it is not a supporter of combustion, except to substances 
very avid of oxygen. 82 

Nitrogen Trioxide — N 2 3 and Nitrous Acid — HN0 2 . — Ni- 
trous acid is known only in its salts, the nitrites. These are pro- 
duced in nature by the oxidation of nitrogenous organic matter 
in the presence of certain forms of microscopic life. 

This nitrification occurs in waters polluted with organic matter, 



50 Put 5 Cc. of NH 4 N0 3 in a side-neck test-tube with cork and delivery-tube 
(Fig. 8). Collect gas over warm water; note that glowing match-stick bursts 
into flame when thrust in. 

81 Copper turnings, clippings, or wires are placed in a flask, and nitric acid 
diluted with half its volume of water is poured in, and the flask set in cold 
water. Red fumes soon fill the flask, but when these have escaped the gas 
appears colorless, turning red, however, on reaching the air. The colorless gas 
is collected over water. 

82 The student might use the apparatus shown in Fig. 7, but must be exceed- 
ingly careful not to inhale the fume's. Collect two cylinders of N 2 2 : (a) 
Into one introduce burning phosphorus; it burns with great brilliancy, (&) 
To the other add a few drops of CS 2 and agitate to mix the vapor and gas; 
then ignite with a flame, and note the blinding, bluish-white blaze, remark- 
ably rich in chemical rays. 



PART I. — INORGANIC CHEMISTRY. 



59 



and normally in the soil, where the acid so formed combines with 
bases. Hence, nitrites in water is evidence of previous contami- 
nation with nitrogenous matter. Further oxidation forms nitrates. 

Nitrcgfn Tetroxide — N 2 4 — occurs in company with N 2 3 in 
the brown fumes given off whenever nitric acid is decomposed, as 
in certain laboratory and manufacturing processes.^ The effect of 
breathing air thus contaminated is to produce chronic inflamma- 
tion of the respiratory tract. If the vapor be more concentrated 
the effects are more acute and serious. At first there is only a 
cough, in two or three hours a difficulty in breathing, and in about 
twelve hours, death. The remedy is ventilation. 

Nitrogen Pentoxide — N 2 5 — is of no medical interest. 

Nitric Acid — HN0 3 {Aqua Fortis) — occurs in traces in the 
atmosphere and as nitrates in the soil. (See Nitrites.) 

Fig. 26. 




Prepared 'by distilling a nitrate with sulphuric acid/ 1 
2KXO3 + H 2 SO, = K 2 SO, - 2HX0 3 . S * 

83 In a side-neck test-tube (Fig. 26) strongly heat some dry Pb 2NG 3 and 
condense the fumes in a test-tube in a freezing mixture of ice and salt. 

81 In the laboratory nitric acid may be prepared with the apparatus shown in 
Fig. 15. Equal parts of sodium nitrate and sulphuric acid are heated in the 
retort A. The nitric acid produced is vaporized by the heat and recondensed 
in the tube B kept cool by an outer tube C, through which flows a stream of 
water from an elevated vessel. The acid is collected in the vessel D. 

86 The student had better use the apparatus shown in Fig. 26. 



60 ESSENTIALS OF CHEMISTRY. 

Physical Properties. — Heavy liquid and colorless, but if old and 
exposed to light it becomes yellow or orange from presence of 
N,0 2 and N 2 4 . Like all nitrates, it is soluble in water. 

Chemical Properties. — HN0 3 readily gives up a portion of its 
oxygen, and hence is an energetic oxidizer. Many organic sub- 
stances, as cotton, glycerine, etc., undergo in contact with HNO* 
a process of nitration in which the radical N0 2 is substituted for 
H, and they (gun-cotton, nitroglycerine, etc.) are much more un- 
stable, combustible, and even explosive. HN0 3 coagulates albu- 
min and stains albuminoid bodies a permanent yellow. 86 

Medical Properties. — The officinal nitric acid contains 68 per 
cent, and the dilute 10 per cent of HNO :> The strong acid is a 
a powerful escharotic, but the dilute is a valuable digestive tonic. 

PHOSPHORUS (light-bearer) . Occurs, combined with oxygen, 
in the ancient, unstratified rocks. These disintegrate and form 
soil, from which the phosphorus passes into the organisms of 
plants, and thence into the bodies of animals, being present in 
every tissue, but mainly stored up in the skeleton. First isolated 
by Brandt in 1669 from urine, but now obtained exclusively from 
bones. 

Physical Properties. — A soft, yellow, solid, resembling un- 
bleached wax. 87 



86 Of the acid formed in the preceding experiment : 

(a) Put a drop on white of egg or fresh meat, and note that the albumen is 
coagulated. 

(d) Place a drop on some dry albuminoid substance, as skin, hair, wool, etc., 
and note the yellow stain, not discharged by alkalies. 

(c) Moisten a bit of paper or cloth with the acid and dry gently; note that 
it burns like tinder. 

(d) Add a few drops to a solution of indigo or other organic dye, and note 
the oxidizing and bleaching effect. 

(e) To some turpentine warmed in a test-tube, add the strong acid; it in- 
flames. 

(/) Lay a drop on clean copper or tin, and note the red fumes. 

(§•) Mix in a test tube equal volumes of H 2 S0 4 and an aqueous solution of 
FeSG 4 , and when cool, add HNO H or any other nitrate; note a brown colora- 
tion, disappearing on heating or even shaking. 

b ~ When heated to 500° F. in an atmosphere incapable of acting upon it, 
phosphorus is converted into a reddish-brown powder, which, unlike ordinary 
phosphorus, is not poisonous, not inflammable, and insoluble in the ordinary 
solvents. 



PART I. INORGANIC CHEMISTRY. 6 1 

Chemical Properties, — Very inflammable/ 5 so kept under water ; 
exposed to the air, it undergoes a slow combustion, emits the 
odor of ozone, and is luminous in the dark. 

Physiological — Liable to inflame from careless handling, and 
burns by it are difficult to heal. In medicinal doses, a nerve 
tonic and aphrodisiac ; in larger quantities a virulent poison and 
gastro-irritant. Sometimes given with homicidal intent, but more 
frequently taken accidentially as rat poison, tips of matches, etc. 
Workmen in match factories suffer from irritation of stomach and 
bowels, caries of teeth, necrosis of bones, especially of lower jaw, 
and from fatty degeneration of various organs. This maybe pre- 
vented by using the red allotropic variety, which is harmless. 

No good antidote. Evacuate the stomach ; give copper sul- 
phate 8 ' J as emetic and antidote : give old turpentine, the ozone of 
which oxidizes the P. Avoid fats, for they dissolve it. 

Tests. — (i) Shines in the dark; (2) emits garlicky odor. 

Phosphine — PH 3 (Phosphoretted Hydrogen.) — Occurs mixed 
with other hydrides of P in the gases arising from decomposing 
animal or vegetable matters, especially under w T ater ; hence seen 
as the ignis fatuus, or " Will-o'-the-wisp," over marshes and 
graveyards. 

Prepared by boiling phosphorus in a solution of caustic potash. 90 

Properties. — Colorless gas of a garlicky odor; inflames spon- 
taneously upon coming in contact w T ith the air ; very poisonous, 

88 Dissolve some phosphorus in carbon disulphide. Pour this on a sheet of 
filter paper hung on a retort stand. Soon the solvent evaporates and leaves 
the phosphorus in such a fine state of division that it inflames spontaneously. 

89 Place a clean bit of phosphorus for a minute in a solution of copper sul- 
phate. Remove, and note the coating of metallic copper. 

1,0 Into a retort, whose delivery tube dips under water in a dish (Fig. 27), 
add liquor potassae and a few bits of phosphorus. Expel the air by passing 
hydrogen or illuminating gas through the retort, or by adding a few drops of 
ether, the vapor of which does the same thing. On applying heat the hydro- 
gen or illuminating gas or ether vapor first escapes, then come bubbles of 
PH.,, each of which, as it bursts into the air, ignites spontaneously, forming 
beautiful rings of white smoke rotating on their circular axes. These may 
ascend to the ceiling if the air be still. 



62 



ESSENTIALS OF CHEMISTRY. 



destroying the oxygen carrying power of the blood, which after 
death is found to be dark-colored, with a violet tinge. 

Fig. 27. 




Oxides and Oxacids of Phosphorus. — These are analogous to 
those of nitrogen, except that several members are missing and 
that the oxides, in combining with water to form their respective 
acids, may take three or two or one molecule of H 2 0, and each 
oxide thus form three different acids, distinguished by the pre- 
fixes, " ortho-," " pyro- " and " meta- ; " for example :— 

P A 1 + 3H 2 = H S P 2 8 = 2H 3 P0 4 = Orthophosphoric acid. 

Phosphorus J + 2 H 2 = H 4 P 2 7 = Pyrophosphoric acid. 92 

Pentoxide.-' 1 I -f H,0 = H 2 P 2 6 = 2HPO3 -= Metaphospboric acid. 

Rl A little stand in the middle of a dinner plate supports a capsule in which 
is put a bit of phosphorus freed from adhering water. This is ignited and 
covered with a bell-jar. The jar is filled with clouds of P,0 5 , which, aggre- 
gating, fall into the plate like a minature snow storm. 

92 Place a few crystals of Na 2 HP0 4 in a dish and heat till it melts and loses 
a part of its water; dissolve the residue (Na 4 P,0 7 ) in water and test with 
AgN0 3 solution; note the white precipitate of Ag 4 P 2 7 . 



PART T. INORGANIC CHEMISTRY. 63 

The "ortho-" acids and salts are the ones so generally used 
that when the " pyro- " and " meta- " are not specified, the 
" ortho- " are meant. 

Hypophosphorous Acid. — This acid is seldom prescribed, but 
the hypophosphites in powder, or better in pill or syrup, are much 
employed, especially in anaemia, tuberculosis, etc. It should be 
remembered in prescribing, especially with reducible metallic 
salts, that the hypophosphites are deficient in oxygen and strong 
reducing agents. 

Phosphorous Acid and the Phosphites are seldom prescribed 
in medicine and of but little importance : prone to oxidize into 
phosphoiic acid and phosphates. 

Orthophosphoric Acid. — Never found free, but is widely dis- 
tributed in its salts, the phosphates, in the tissues of plants and 
animals, especially in bones, and in the earth, the " phosphate- 
beds ' ? of our southern sea-coast being its principal source. The 
officinal acid is, or should be, made from phosphorus and nitric 
acid. Being the phosphoric acid most used in medicine (the 
other two are poisonous) it is usually called simply " phosphoric 
acid." A transparent, sour, syrupy liquid : but when free from 
water and cold it is in rhombic crystals, the so-called glacial 
phosphoric acid. Heated above 200 C. (392 F.) it is con- 
verted into pyrophosphoric and metaphosphoric acid. 

Phosphoric acid does not coagulate albumin, and in the diluted 
form is much used as a digestive tonic. 

Its usual tests are, (a) with AgN0 3j a yellow precipitate soluble 
in nitric acid and ammonia: (b) with the magnesian fluid of 
the U. S. P., a white precipitate soluble in acids. 93 

ARSENIC. — Arsenic [arsemttn) occurs mostly as sulphide, 
usually associated with other metals. The ore is roasted, and the 
resulting oxide heated with carbon (charcoal) yields the metal. 
This is a brittle, steel-gray crystalline, solid possessing a marked 
metallic lustre. Pleated out of contact with air it sublimes ; in 



^ Boil some match-heads in a test-tube with dilute nitric acid; neutralize 
with ammonia and test this solution as indicated above for H 3 P0 4 . 



64 ESSENTIALS OF CHEMISTRY. 

air it burns with a bluish-white flame emitting the odor of garlic 
and white clouds of As 2 3 . It combines with many elements, its 
compounds with metals (arsenides) resembling alloys. Used in 
pyrotechny, the manufacture of shot, pigment and fly-poison. 
All its compounds are poisonous. 

Hydrogen Arsenide — AsH 3 — Arsine — is of great practical 
interest to the toxicologist, as its formation constitutes one of the 
best and most delicate tests for arsenic, for it is formed wherever 
arsenic finds itself in the presence of nascent hydrogen, i. <?., 
whenever hydrogen is generated in the presence of an arsenical 
compound. It is so extremely poisonous that chemists (e. g., 
Gehlen, in T815) have lost their lives by inhaling it accidentally. 

Arsenous Iodide — Asl 3 — Prepared by fusing together atomic 
proportions of its constituent elements. The official " Donovan's 
Solution" (liq. arseni et hydrargyri iodidi) contains 1 per cent, 
each of Asl 3 and Hgl 2 , and is considered the strongest alterative 
in the materia medica. 

Arsenous Sulphide — As 2 S 3 — occurs native as orpiment; pre- 
pared by precipitating an arsenous compound with H 2 S ; a bright 
yellow powder, insoluble in water and acid solutions, but soluble 
in alkaline. Another sulphide is realgar, As 2 S 2 . Both are used 
as pigments — orpiment as a yellow and realgar as a red. 

Oxides and Oxacids. — These are analogous to those of phos- 
phorus, and like them form ortho-, pyro- and meta- acids. 

c + 3"H 2 = 2H 3 As0 3 == Orthoarsenous acid. 
As A J _j_ 2 h 2 = H 4 As 2 5 = Pyroarsenous acid. 
Arsenous Oxide. [ + nfi _ 2HAs0a ^ M etarsenous acid. 

r -\- 3H 2 = 2H 3 As0 4 = Orthoarsenic acid. 
AS A J _|_ 2 h 2 o = H 4 As 2 7 = Pyroarsenic acid. 
Arsenic Oxide. ( + nQ _ 2HAs q 3 = M etarsenic acid. 

Arsenous Oxide — As 2 3 . Arsenic, White Arsenic, Ratsbane, 
Arsenous Acid, — This is not only the most important compound 
of arsenic, but the most important of toxic agents, whether we 
consider the deadliness of its effect or the fatal frequency of its 
jad ministration. When recently made it is in glassy lumps, which 



PART I. INORGANIC CHEMISTRY. 65 

on exposure become crystalline and opaque. When sublimed it 
is deposited again in brilliant octahedral crystals. It is odorless, 
almost tasteless — slightly sweetish. When powdered arsenic is 
thrown upon water it does not all sink, notwithstanding its heavi- 
ness, but floats, showing a repulsion of the w r ater. Very slightly 
soluble in water ; even boiling water dissolves less than two per 
cent. If the water be made acid or alkaline, it dissolves more 
readily. When arsenic dissolves in water it forms arsenous acid, 
H 3 As0 3 . 

There are two officinal solutions, each containing one per cent, 
of arsenic : (i) Liq. acidi arsenosi, in which the water is acidu= % 
lated with HO; (2) Fowler's Solution, liq. potassii arsenitis, in 
which the water is made alkaline by K 2 C0 3 . 

Arsenic Oxide. — Arsenic pentoxide is made when arsenous 
oxide (As,0 3 ) is treated with an oxidizing agent, as nitric acid. 
It is quite soluble in water, with which it forms a series of arsenic 
acids (ortho-, pyro- and meta-) analogous to the phosphoric acids. 

Toxicology of Arsenic. — The deadly effect of arsenical com- 
pounds has been known from remote antiquity, and they have 
probably been more used for homicidal purposes than all other 
toxic agents combined. Although chemistry has made its detec- 
tion easy and certain, arsenic is so cheap, so readily administered 

WHITE ARSENIC (Dry). 

94 Inspect the powder first with the naked eye and note its color, crystalline 
form, etc. 

95 Toss a little on water and note that it does not dissolve but floats, though 
a few larger grains may sink. 

96 Heat a grain on a knife blade; it volatilizes with a white smoke and leaves 
no residue. Take care not to inhale the fumes. 

97 Take a five-inch piece of small glass tubing and melt it into two portions. 
Into the open end of one, drop a minute grain and heat; the arsenic sublimes,, 
leaving no residue at the bottom of the tube, but gathering in a ring of octa- 
hedral crystals (Fig. 28) around the tube in its cooler portion. 

98 Into the other tube put some arsenic, as above, and also powdered char- 
coal a quarter-inch deep; hold the tube in the flame so as to heat the charcoal 
first and then the As.0 3 as it sublimes will give up its oxygen to the charcoal 
(reduction) and be deposited above the charcoal in a lustrous, bright ring of 
metallic arsenic (Fig. 29). 



66 ESSENTIALS OF CHEMISTRY. 

to the unsuspecting victim, and so deadly, that it is still a favorite 
with the murderer. Owing to the extensive use of arsenical com- 
pounds as insect-powders (Paris green, etc.), and as pigments for 
wall-paper, toys, confectionery, etc., cases of accidental poisoning 
are quite common. 

Few physicians have the training and facilities to undertake an 
extended analysis, but they should all know the simpler tests, so 
as to promptly recognize the nature of the poison and combat it 
intelligently and successfully. Besides, the physician, being early 
in the case, can by wise precautions prevent breaks in the chain 
#of evidence ; protecting the prisoner if innocent, and closing loop- 
holes of escape if guilty. If foul play is suspected, he should 
commit all his observations to writing, for notes to be admitted as 
evidence must be the original ones taken at the time. Having 
collected the urine, faeces, vomit, and the suspected vehicle of the 

WHITE ARSENIC (in Aqueous Solution). Boil white arsenic (i Cc.) in 
a small flask or large test- tube and submit successive portions of about 5 Cc. 
each, to the following tests : — 

99 Hydrogen Sulphide Test. Pass bubbles of H 2 S (see page 47) and note 
the yellow precipitate of As. 2 S 3 . 

100 Ammonio- Silver Nitrate Test. Add cautiously ammonia water to 
AgN0 3 solution until the brownish precipitate first formed is almost all dis- 
solved, avoiding excess of ammonia. Add a few drops of this solution to the 
arsenic water, and note yellow precipitate of Ag 3 As0 3 . 

101 Ammonio- Copper Sulphate Test. Add ammonia water to CuS0 4 solution 
till bluish precipitate first formed is almost dissolved; add a few drops to the 
arsenic water and note the green precipitate of CuHAs0 3 (Scheele's green). 

102 Repeat these three tests on much more dilute solutions of arsenic, and 
note their extreme delicacy, but take care to avoid excess of the alkali which 
would hold up the precipitate or redissolve it. 

ARSENICAL MIXTURES. The foregoing tests are applicable to pure 
arsenic or simple solutions, and not to suspected food, stomach-contents, etc. 
Extemporize a " suspected specimen *' by poisoning some coffee with " Rough 
on Rats " or other common form of arsenic, and test portions as follows : — 

m Plating Test (Reinsch's). Acidulate 5 Cc. of the suspected solution 
with 1 Cc. of HC1; add a strip of clean arsenic-free copper (such copper 
foil is sold) and boil ten minutes; note the gray deposit of arsenic on the 
copper. To prove it is arsenic, remove the copper and wash and dry it, 
handling and warming it very gently to avoid removing the plating, and then 
heat in a clean, dry test-tube. Note a sublimate of As 2 3 , which in turn may 
be dissolved off by boiling water in the tube, and when cool submitted to the 
other tests. 



PART I. INORGANIC CHEMISTRY. 



67 



poison, and having tested some or all of them to verify his suspic- 
ion, he should place them under seal or lock and key. He should 
carefully reserve his opinion, lest he do injustice to the innocent 
or warn the guilty. In case of death, the coroner should be 
notified and an autopsy held in the presence of the chemist if 
possible. The stomach and entire intestinal canal, ligated at both 
ends, half of the liver, the whole brain, spleen, one kidney, and 
any urine remaining in the bladder should be saved. These, if 
possible, should be preserved in separate jars, to which a little 
pure chloroform may be added to prevent decomposition. These 
jars must be new and clean, closed with new corks or glass — not 
zinc caps. They are then to be labeled, and also sealed and 
stamped, so they cannot be opened without detection, and as soon 
as possible turned over to the chemist or prosecuting officer. 

The symptoms of arsenical poisoning 'are those common to all 
intense irritants, viz., nausea, vomiting, burning pain in the epi- 

Fig. 28. Fig. 29. 





gastrium, purging, cramps, thirst, fever, rapid pulse, etc., ending 
in collapse. Smallest fatal dose is two grains, and death usually 
occurs in twenty-four hours. 

Treatment. — Remove any unabsorbed poison from the stomach 
by emetics or stomach-pump. The best antidote {}i is freshly pre- 

104 Antidote — Demonstration. — Pour into a beaker an inch of FeCL. solution, 
add ammonia water until alkaline, strain the precipitate of Fe3HO on a cloth 
and wash till clear of ammonia, and then stir fresh precipitate into another 
beaker containing an inch of arsenic water. After five minutes, hlter the mix- 
ture and show by the foregoing tests that the filtrate is free of arsenic. 



68 



ESSENTIALS OF CHEMISTRY. 



cipitated ferric hydrate, made by adding aqua ammoniae to a 
solution of a ferric salt. " Dialyzed iron," being a solution of 
ferric hydrate, may be used. It should be given at frequent 
intervals and in tablespoonful doses. 

Tests for Arsenic. — The ordinary tests for arsenic are given in 
the laboratory notes below. The student should practice until 
he can perform them with readiness and accuracy. 

The Hydrogen {Marsh's) Test depends on the fact that AsH 3 is 
always formed whenever hydrogen is generated in the presence of 
any arsenical compound. Generate hydrogen (Fig. 30) in the 



Fig. 30. 






usual way (Zn + H 2 S0 4 ), and if the chemicals are pure (free from 
arsenic), the gas burns with a pale yellowish flame, without odor, 
and does not stain a porcelain dish held in the flame. Then pour 
into the generator some of the suspected solution. If arsenic be 
present, there is an odor of garlic ; the flame becomes bluish- 
white, and a cold porcelain dish held in the jet (Fig. 31) so 
chills the flame that only the H burns, and the As is deposited on 
the porcelain as a brilliant metallic film. If the delivery tube 
be heated (Fig. 32), the passing AsH 3 is decomposed, and me- 
tallic arsenic is deposited farther out in the tube in a film of the 
the same character as that on the porcelain. 



PART I. INORGANIC CHEMISTRY. 



6 9 



This may be distinguished from the film formed by antimony 
under similar circumstances by (1) its greater metallic lustre, and 
(2) by its dissolving on the addition of chlorinated soda (Labar- 
raque's solution) ; (3) moisten the spot with nitric acid ; evapo- 
rate the acid ; a white stain is left, which is colored a red by 
AgN0 3 and yellow by H 2 S. The flame should now be extinguished 
and the delivery tube made to dip into a solution of AgN0 3 . 

Fig. 31. 




This will be blackened, and if overlaid with aqua ammoniae, a 
yellow precipitate will appear at the junction of the two fluids. 

ANTIMONY {stibium) occurs native, and usually as a sul- 
phide. Prepared by roasting the sulphide, and heating with 
charcoal the oxide thus obtained. 

Properties. — A bluish-white, crystalline solid, with a brilliant 
metallic lustre. Resembles metals and forms alloys. In chemi- 
cal reactions it plays the role of positive and negative radical 
with equal facility. 

Used in alloys, as type metal, Babbit's metal, Britannia, etc., to 
which it gives hardness and causes them to expand and fill the 
molds on solidifying. The metal is not used in medicine and 
pharmacy, most of the compounds being obtained from the 
sulphide. 

Hydrogen Aktimonide. — SbH 3 {Stibine), corresponding to 
AsH 3 . This gas is formed wherever hydrogen is generated (nas- 
cent) iu presence of a reducible antimony compound. 

Antimonious Chloride. — SbCL. At ordinary temperatures a 
yellow semi-solid ; hence called butter of antimony. On addi- 



70 ESSENTIALS OF CHEMISTRY. 

tion of considerable water it decomposes, precipitating a white 
powder, the oxychloride (SbO.Cl), 105 formerly called powder of 
alga roth. 

Antimony Oxides and Oxacids. — These are analogous to those 
of phosphorus and arsenic, but of little importance either in med- 
icine or the arts. 

Antimonious Oxide. — Sb 2 ;} . Prepared by treating the oxy- 
chloride with sodium carbonate to remove the chlorine. A whit- 
ish, insoluble, volatilizable powder. 

Antimony and Potassium Tartrate. — Tartar Emetic. — Made 
by boiling 3 parts of Sb 2 Q 3 and 4 parts of cream of tartar in water, 
filtering and evaporating. 

2KHC 4 H 4 6 + Sb 2 3 = 2K(SbO)C 4 H 4 6 + H 2 
Potassium Bitartrate Tartar Emetic 

Colorless crystals of a sweetish, metallic taste ; soluble in water 
and slightly so in alcohol. The only officinal salt of antimony, 
soluble without decomposition, and therefore more used in medi- 
cine than the others combined, e. g., in the officinal vinutn anti- 
monii, unguentum antimonii and syrupus s cilice compositus. 

Antimonious Sulphide. — Sb 2 S 3 , the principal ore of antimony ; 
occurs native in black, lustrous masses. It may be precipitated 
from any antimonial solution by H 2 S as an orange powder, which 
is black when thoroughly dried. 

Medical. — Antimony salts, especially the soluble tartar emetic, 
are local irritants externally, expectorants in doses of fractions ot 
a grain, emetics in larger doses, and in excessive doses gastro- 
intestinal irritants; one and a half grains (0.1 Gm.) have killed, 
though recovery has occurred from vastly larger quantities, owing 
to the prompt emesis it produces. 

Antidote. — Tannic acid forms with it an insoluble (and there- 
fore harmless) compound, but its best antidote is ferric hydrate, 

105 SbO and BiO, called respectively antimonyl and bismttthyl, are univalent 
radicals, because two valences of the trivalent element being satisfied by the 
bivalent O, only one free valent is left. 



PART I. — INORGANIC CHEMISTRY. 7 I 

the same as for arsenic : so one need not wait to determine if the 
poisoning be by arsenic or antimony. 

Tests. — The presence of antimony may be detected by the 
plating and hydrogen tests just as arsenic, but differentiated 106 
from that element by the sublimate from the plating being amor- 
phous and the metallic mirror being insoluble in chlorinated soda 
solution ; also by H,S giving an orange-red precipitate soluble in 
ammonium sulphide and in strong HC1, but unlike As,S 3 insoluble 
in ammonia water. 

BISMUTH occurs native and as a sulphide. Prepared by 
roasting the sulphide in air, and reducing the resulting oxide with 
charcoal. 

Properties. — A brittle, white metal, 107 with a bronze tint ; vola- 
tilizes at a white heat. Forms compounds closely analogous to 
those of Sb, but is more positive, and plays the negative role with 
less facility. 

Used in alloys ; e. g., pewter and stereotyping metal ; the latter 
melts in boiling water. 

Bismuth Nitrate — Bi3N0 3 . — Formed by treating bismuth with 
nitric acid.' 03 Dissolves in a little water, but if much water be 
added it decomposes, with precipitation of — 

Bismuth Sub ui irate— BiOXO- 6 (Bismuth Oxynitrate) m — A 
white, tasteless powder, much used in medicine and as a cos- 
metic (pearl white). 

Bismuth Subcai'bonate — (BiO) 2 CO. s . — Similar to the preceding 
in constitution, properties and uses. 110 

106 Repeat the hydrogen sulphide test (99), the hydrogen test, the plating 
test (103), and demo?istration 104, using a solution of tartar emetic instead 
of arsenic, and note the peculiarities of antimony. 

107 Metallic Bismuth. Secure a lump of the metal and study its physica 
properties. 

108 Bismuthons Nitrate. Heat an excess of the metal with strong HN0 3 and 
preserve the solution (Bi3N0 3 ) for the subsequent experimentation. 

109 Bismuth Subnitrate. Let fall a few drops of the solution into a beaker 
of water and note white precipitate of BiOX0 3 . 

110 Bismuth Subcarbonate. To a second portion add ammonium carbonate 
and note white precipitate of (BiO) 2 C0 3 . 



72 ESSENTIALS OF CHEMISTRY. 

Bismuth and Ammonium Citrate.— Obtained in pearly scales 
by dissolving the citrate in dilute ammonia-water, evaporating to 
a syrupy consistence and spreading on glass to dry. Being very 
soluble it is the preparation used in making the popular elixirs of 
bismuth. 

Physiological. — The bismuth salts are tonic, sedative, mildly 
astringent and antifermentative. Used to allay gastro-intestinal 
irritation. Occasionally the irritation is increased from presence 
of arsenic which unscrupulous manufacturers often fail to remove 
as the Pharmacopoeia directs. 

When preparations of bismuth are taken, the stools are black- 
ened by the sulphide formed with the H 2 S in the intestines. In 
severe cases of diarrhoea, with acid fermentation, this blackening 
does not occur, and its reappearance is a sign of improvement. 

V. Carbon Group. 

Carbon (carbo, a coal) , C, 12 

Silicon (si/ex, a flint), Si, 28 

Tin (Stannuni), Sn, 118 

Lead (Plumbum), Pb, 207 

Platinum Pt, 195 

Iridium Ir, 193 

Osmium, Os, 191 

Palladium, Pd, 106 

Ruthenium, Ru, 101 

Rhodium, Rh, 104 

Each element is bivalent and quadrivalent. Their dioxides 
form with water dibasic acids : — 

C0 2 + H 2 = H 2 C0 3 , Carbonic acid. 
Si0 2 + H 2 - H 2 Si0 3 , Silicic acid. 
Sn0 2 + H 2 — H 2 Sn0 3 , Stannic acid. 
Pb0 2 + H 2 = H 2 Pb0 3 , Plumbic acid. 

11 ' Bismuthous Sulphide. Through a third portion pass H 2 S and note black 
precipitate of Bi 2 S 3 . 

112 To another portion add a bit of zinc and note black deposit of metallic 
Bi. 



PART I. INORGANIC CHEMISTRY. 



73 



CARBON occurs free in its three allotropic forms, diamond, 
graphite, and coal ; combined in carbonates and in all animal and 
vegetable substances. All its forms are probably traceable to 
organized life. 

Diamond. — Geological history unknown ; transparent crystal- 
line body of great brilliancy ; hardest substance known. Used as 
a gem and for cutting glass, etc. 

Graphite (to write). — Owing to its resemblance to lead it has 
been called black lead or plumbago ; almost pure carbon. Used 
for pencils, crucibles, stove polish, etc., and as a lubricant. 

Coal. — Mineral coal is a black substance, compact in texture, 

Fig. 33. 



Fig. 34. 




the remains of vegetable life of past ages. Charcoal is obtained 
by burning heaps of wood with a limited supply of air. 113 The 



113 Charcoal by incomplete combustion. Push a lighted match-stick slowly up 
into the mouth of a small test-tube. (Fig. 33.) Note the incomplete combus- 
tion, and that the stick is converted into charcoal. 

6 



74 ESSENTIALS OF CHEMISTRY. 

volatile constituents pass off, leaving the carbon as a light, porous 
substance, retaining the form and structure of the wood. 114 
Animal charcoal is made by heating animal matters in closed 
iron retorts. Charcoal, especially animal, is a valuable absorbent 
of odorous gases 115 and coloring matters. 116 

Soot or lampblack is a very finely divided carbon, deposited by 
the heavy smoke from the incomplete combustion of tar, oils, or 
other substances rich in carbon. 117 

Properties. — Free carbon is solid at all temperatures, and in- 
soluble in all menstrua. Ordinarily, free carbon is unaffected by 
chemical agents, but at high temperatures it surpasses most other 
elements in its avidity for O. Hence it is used to separate the 
metals from their oxides. 118 

Carbon Monoxide — CO. — Occurs whenever carbon is burned 
with an insufficient supply of air, as in anthracite stoves and 
furnaces, and in coal-gas, but never occurs in nature. 

Prepared in the laboratory by heating oxalic acid, 119 or potas- 

114 Pack match-stick- side by side in the lower part of a small tube and heat 
as strongly as the glass will stand. Note the gases, vapors and tarry fumes 
evolved from the destructive distillation. When these have about ceased to 
come off, remove the tube from the flame and cork it up. When cool exam- 
ine the charcoal residue. 

115 Fill a test-tube with ammonia gas over mercury (Fig. 34). Introduce a 
piece of charcoal recently heated. The gas is absorbed, as is shown by the 
rapid rise of the mercury. 

116 To a solution of indigo, cochineal, or potassium permanganate or beer in 
a flask, add some animal charcoal, shake up and filter. The filtrate is colorless, 
and in case beer is used it has also lost its bitter taste. 

117 Lampblack. — Hold a cold porcelain dish in a candle flame, the flame of 
a gas jet or of a Bunsen burner with the air-holes closed. Note the deposit of 
lampblack. 

118 Into a slight depression in a piece of charcoal lay some metallic oxide, 
e. £•., lead oxids; heat with a blow-pipe. The oxide is reduced by the heated 
charcoal around it, and globules of the metal appear which coalesce into a 
bright button. 

119 From Oxalic Acid and J7 2 SO v — Into a side-neck test-tube put 5 gm. of 
oxalic acid and K 2 S0 4 enough to cover it. Connect a delivery tube and wash- 
bottle containing KHO, (or use flask as arranged in Fig. 35), and heat strongly 

H 2 C 2 4 +H 2 SO^H 2 S0 4 + C0 2 +H 2 + CO. 

The C0 2 is absorbed by the KHO in the wash-bottle, and the CO is collected 
in tubes over water. 



PART I. INORGANIC CHEMISTRY. 



75 



sium ferrocyanide, with sulphuric acid, or by heating a mixture of 
charcoal and cupric oxide. 1 '- 

Properties. — Colorless, odorless, tasteless gas ; burns with a 
pale blue flame ; very poisonous, combining with the coloring 



Fig. 3^. 




Making CO. 

matter of the blood corpuscles, and destroying their oxygen- 
carrying power. Artificial respiration is of little use. Transfusion 
of blood is the most promising treatment. After death the blood 
remains scarlet. The sources of danger are open charcoal fires, 
defective draught in stoves and chimneys, and illuminating gas 
escaping into bed-rooms. 
Carbon Dioxide — COo. 

C0 2 +H 2 0=H 2 C0 3 — Carbonic acid. 

^Let two students working together prepare carbon monoxide by incom- 
plete combustion of carbon. Mix equal parts of powdered charcoal and black 
oxide of copper, and put into a side-necked test-tube with delivery tube as in 
Fig. 8; heat as strongly as the glass will stand, and collect the CO in tubes 
over water. Note the properties of the gas, and search the residue for gran- 
ules of metallic copper. 



J 6 ESSENTIALS OF CHEMISTRY. 

Occurs sparingly (.0003) in the atmosphere, as a result of 
animal respiration, vegetable decay, and combustion. Plants 
absorb it, appropriating the carbon and returning the oxygen to 
the air. 

It often accumulates in cellars, beer-vats, wells, etc., where it is 
called choke-damp. 127 

Prepared by burning carbon ; but most conveniently, in the 
laboratory, by decomposing a carbonate with an acid. 121 

CaC0 3 +2HCl=CaCl 2 +H 2 0+C0 2 . 

Physical Properties. — Transparent, colorless gas, of a pungent 
odor and sour taste. One and a half times as heavy as air. 122 
Water dissolves its own volume. 123 

Chemical Properties. — Neither burns nor supports combus- 
tion. 124 In water it exists as carbonic acid— H 2 C0 3 . On 
attempting to concentrate this dilute solution the acid decom- 
poses again into water and C0 2 ; hence wet litmus reddened by 
it becomes blue again on drying. 

The carbonates of the potassium group are all soluble, and not 
decomposable by heat, all others are insoluble 125 and decompos- 
able by heat. 

121 Put about 30 Gm. (one ounce) of marble dust (CaC0 3 ) in a flask with 
delivery tube and pour in HC1 through the funnel; collect the gas by down- 
ward displacement in a good -sized glass jar. Note its color and behavior to 
moistened blue litmus paper; taste and smell it by sucking it up through a 
glass tube. 

122 To show the weight of carbon dioxide: (1) Pour it from one vessel to 
another. (2) Blow soap bubbles and allow them to fall into a wide vessel 
containing this gas. As soon as they reach the surface of the gas they stop 
and float upon it. (3) Pour a large beakerful of the gas into a light paste- 
board box that has been balanced on a pair of scales. The box will at once 
descend. 

123 That water will dissolve a greater quantity of carbon dioxide under pres- 
sure is shown by the rapid evolution of the gas whenever a bottle of soda or 
other carbonated water is opened and the pressure thereby removed. 

124 Set a candlestick, holding several lighted tapers at different heights, in a 
large jar. Carbon dioxide is introduced at the bottom, and extinguishes the 
tapers one by one as the vessel fills up to their levels. 

125 To each of four test-tubes add, respectively, solution of CaCl 2 , MgS0 4 , 



PART I. INORGANIC CHEMISTRY. 



77 



Uses. — C0 2 is the principal food of plants. Combustion 1 - 6 and 
the oxidation of decaying vegetation and the respiration of 
animals 127 add vast quantities to the air; plants absorb this and 
the green coloring matter (chlorophyl) in their leaves decomposes 
it, the carbon going into the structure of the plant and the 
oxygen returning to the air. Besides its employment in the 
manufacture of carbonates, CO, is extensively used in beverages, 
making them effervescent, sparkling and of an agreeable, pungent 

Fig. 36. 




taste. " Soda water" is simple water charged with about 5 vol- 
umes of C0 2 and flavored with any desired fruit-syrup. For this 
purpose, C0 2 is now sold liquefied in strong steel cylinders under 
a pressure of 40 atmospheres (600 lbs.). The evaporation of 
this liquid is sometimes used in laboratory work for the produc- 
tion of intense cold ( — no C). 

FeS0 4 , and Pb(C 2 H H 0o) 2 . Pass C0. 2 into each and note the precipitation of 
the carbonates of these metals. Add a few drops of acid to each and note 
that the precipitates dissolve with effervescence of CO. . 

126 Set a short candle into a glass jar and put the cover on. When the 
candle is extinguished remove it and add lime-water and shake thoroughly. 
Note the white precipitate of CaC0 3 . 

lil That this gas accumulating in wells can be bailed out in buckets, may be 
illustrated by dipping it out of a glass jar and pouring it on to a small lighted 
candle. 



78 ESSENTIALS OF CHEMISTRY. 

Tests. — (i) The gas (15 per cent, and over) extinguishes a 
flame ; (2) precipitates lime-water; (3) carbonates effervesce on 
adding a strong acid. 

Physiological — If the gas be undiluted, death is immediate 
from spasm of the glottis. If somewhat dilute (15 to 30 per 
cent.) there is loss of muscular power, anaesthesia, and death 
without a struggle. If quite dilute (5 to 10 per cent.) headache, 
giddiness, muscular weakness, and sometimes vomiting and con- 
vulsions occur. 

The effects are more serious if the C0 2 comes from combustion 
or respiration, because of the removal of oxygen and the admix- 
ture of the deadly CO and animal exhalations. 

Treatment. — Fresh air, artificial respiration, and stimulation. 
The preventive is ventilation. 

Ventilation. — More than 7 parts of C0 2 in 10,000 of air is 
oppressive. Taking this as the maximum impurity allowable, 
3,000 cubic feet of fresh air per hour is needed by each person, 
and more in case of disease or when lamps are burning. To 
secure this in a room containing 1,000 cubic feet (10X 10X10), 
the air must be changed three times an hour. This would give a 
draught not uncomfortable or injurious. If the draught be prop- 
erly distributed, a breathing space of 500 cubic feet changing six 
times an hour would be unobjectionable. Ventilation may be 
secured in two ways, by diffusion and by draught. 

Diffusion. — Gases mingle more rapidly, liquids more slowly, to 
make a mixture of uniform density. 

When two gases of different densities are separated by a porous 
partition, they mingle, the lighter passing through more rapidly 
than the heavier, the rapidity being in inverse ratio to the square 
roots of their densities. 129 



12(5 Two Wolff bottles are half filled with lime-water and arranged as in Fig. 
36. Placing the rubber tube in his mouth, the operator can inspire through 
one bottle and expire through the other. The small amount of carbon dioxide 
in the inspired and the larger amount in the expired air are shown by a white 
precipitate, slight tn the one and dense in the other bottle. 

129 Cement a porous earthenware battery cup at its open end to the top of a 



Fig. 37. 



PART I. INORGANIC CHEMISTRY. ^9 

This diffusion is more active in winter than in summer, because 
, of the greater difference in density of the warm air within the 
house and the cold air without. Damp walls are 
unhealthy, mainly because being no longer por- 
ous they prevent this diffusion. 

Cyanogen — CN or Cy. Univalent because 
N m can satisfy only three valences of C TV . A 
compound negative radical resembling in its 
chemical behavior the elements of the chlorine 
group. 

Prepared by strongly heating mercuric cyan- 
ide. 1 ™ 

Hg(CN),_-Hg-2CN. 

A colorless gas, smelling like peach kernels. 
Burns with a peach-blossom flame; unites with 
metals to form cyanides, the most important 
being — 

Hydrocyanic Acid — H(CN), or HCy — 
Prussic Acid, Hydrogen Cyanide). — Occurs in 
bitter almonds, cherry-laurel water, etc. 

Properties. — Colorless liquid, having an odor 
like peach kernels. For medical purposes only 
a dilute (2 per cent.) solution is used, and 
the dose is from two to five drops. 



funnel tube, the end of which dips into a bottle of colored water, as in Fig. y]. 
Bring down over the cup an inverted bell jar of hydrogen. The light H diffuses 
so much faster into the cup than the air diffuses out of it, that bubbles of gas 
escape rapidly through the water. Remove the bell jar and the conditions are 
reversed. The H now diffuses so rapidly out of the cup that the water is sucked 
up the tube. 

130 Heat Hg2CN in a side-necked test-tube with delivery-tube, and note the 
properties of the CN gas evolved. If mercuric cyanide cannot be obtained, a 
mixture of two parts of thoroughly dried potassium ferrocyanide and three 
parts mercuric chloride may be used. Remember Hg2CN is exceedingly pois- 



131 Experiments 122, 123, 124, 128 and 129 had better be performed by the 
instructor in the presence of the class. 



80 ESSENTIALS OF CHEMISTRY. 

Toxicology, — All the cyanides are very poisonous. One drop 
of the pure acid produces immediate death, and three grains of 
potassium cyanide kills in a few minutes. The respiratory cen- 
tres are paralyzed, and the victim falls and dies in convulsions. 
Poisoning is liable to occur from handling the acid or the cyan- 
ides, which are largely used in the arts, or from eating vegetable 
products, <?. g. peach and cherry seeds containing amygdalin, a 
substance easily decomposing into prussic acid and other pro- 
ducts. Owing to the rapid action of the poison, antidotes are 
usually impracticable. Use artificial respiration and stimulate. 
If the patient survive an hour, the prognosis is good. 

Tests. — fi) Its odor; (2) silver nitrate — white precipitate sol- 
uble in boiling HN0 3 ; ( 3) add ammonium hydrosulphide, evapo- 
rate to dryness, and then add ferric chloride — a blood -red color. 

Cyanates. — Cyanic acid (HCyO) and ammonium cyanate 
( NH 4 CyO) are the most interesting. The latter on being heated 
in aqueous solution forms urea. 

Sulphocyanates are sulpho-salts corresponding to the cyanates 
(oxy-salts), and are good illustrations of the facility with which S 
forms series of compounds analogous to those of O. They, espe- 
cially the potassium and sodium salts, are used as test reagents. 

Compound Cyanides. — Cyanogen shows a great tendency to 
form complex radicals, especially with iron : as ferro cyanogen 
[Fe II (CN) 6 I ] IV or (FeCy 6 ) IV , and ferricyanogen [Fe 1II (CN) 6 I ] VI 
or (FeCy 6 ) VI . These two radicals contain ferrous and ferric 
iron respectively, and with hydrogen form acids (hydracids) 
known as hydro-ferrocyanic acid, H 4 FeCy 6 (tetrabasic), and hydro- 
ferricyanic acid H 3 Fe(CN) 6 or H 3 FeCy 6 (hexabasic) ; the salts 
of these acids are termed ferrocyanides and ferricyanides. 

Potassium Ferrocyanide. — K^FeCyg — commonly called yellow 
prussiate of potash, and potassium ferricyanide — K 3 FeCy 6 — red 
prussiate of potash, are important test reagents. 

The carbon compounds will be further considered under the 
head of Organic Chemistry. 



PART I. INORGANIC CHEMISTRY. 61 

SILICON (also called silica??i) resembles carbon, and occurs 
in three allotropic forms corresponding to coal, graphite and dia- 
mond ; most abundant element after oxygen. It exists in only a 
few compounds, but they constitute the larger part of the earth's 
crust. Its principal compound is its oxide. 

Silicon Oxide — Si0 2 — Silica occurring as sand, chalcedony, 
agate, onyx, quartz, etc., and as a constituent of granite and other 
abundant rocks. Colorless, except when tinted by the oxides of 
certain metals as in the amethyst and other gems ; insoluble and 
unaffected by most reagents except HF and fused alkalies. 

Silicic Acid occurs in two varieties : 

o.-. j -f- 2H 2 == H^SiO.j.orthosilicic acid; 
^ — HoO = H 2 Si0 3 — metasilicic acid, 

When sodium silicate is treated with hydrochloric acid 
N)a,Si 4 -f O4HCI --= 4NaCl : H,Si0 4 ) and the NaCl dialyzed out 
orthosilicic acid remains, colorless, tasteless, and only faintly acid 
to litmus. If this be evaporated and mildly heated it loses one 
molecule of H 2 and becomes metasilicic acid (H,Si0 3 ) which 
by further heating gives off the second H 2 and is converted into 
silica (Si0 2 ). 

Silicates of aluminum and magnesium are very abundant, as 
clay, soapstone, asbestos, etc. Glass is a mixture of several sili- 
cates, usually of sodium, calcium and sometimes lead. It is made 
by melting sand (Si0 2 ) with the carbonates or oxides of the 
metals. The addition of certain metallic oxides gives color ; e. 
g. 9 cobalt gives a blue, manganese an amethyst, and copper a ruby. 
If the glass consist of only an alkaline silicate (<?. g. 9 sodium 
silicate), it is soluble or water-glass, which is largely used in sur- 
gical dressings. 

The Metals. — Occurrence, — Some, as gold and copper, occur free, but 
most of them are found combined with non-metallic elements, especially sul- 
phur and oxygen. 

Preparation. — If combined with sulphur the ore is roasted until the sulphur 
is burned out, leaving the metal as an oxide, which is then heated with carbon 
to remove the oxygen, thus : 

ZnS + 3 = ZnO + S0 2 ; then, ZnO + C = CO + Zn. 



82 ESSENTIALS OF CHEMISTRY. 

Physical Properties. — Very opaque, with a "metallic lustre " (in fine pow- 
der, a dull black) ; bluish-gray, varying between the pure white of silver and 
the dull blue of lead. Yellow gold and red copper are exceptions. In weight, 
varying greatly, as between lithium, specific gravity 0.58, and platinum, specific 
gravity 21.50. Most are solid, except mercury (liquid) and hydrogen (gas- 
eous). All are absolutely insoluble in water as long as they are in the metallic 
state. 

Chemical Properties. — Electro-positive, possessing greal affinity for the non- 
metals and other electro-negative radicals. When two metals are fused to- 
gether the product is an alloy. If one of the metals be mercury, it is called 
an amalgam. Alloys are not chemical compounds, but mixtures, for the 
metals do not unite in definite proportions, and the alloy is not a new sub- 
stance, but one with properties intermediate between those of its constituent 
metals. 

Used mostly in the arts. Of the fifty-five metals only about twenty-six, or 
rather compounds of these, enter the materia medica, and merit our notice. 

TIN. — A bluish-white malleable metal, not corroded by air or 
water ; hence used to form a protective coating for iron and cop- 
per. Tin-ware is usually sheet-iron coated by being dipped into 
molten tin. Tin-foil (thin laminae of tin) is used in wrapping to 
exclude air and moisture. Tin enters into the composition of a 
great many alloys. Alloyed with lead it is easily dissolved, and 
may cause lead poisoning, especially in those using cheap canned 
goods and tobacco wrapped in tin-foil. Powdered tin is some- 
times used as an anthelmintic. 

Tin forms two classes of compounds : the stannous, in which 
the atom is bivalent, and stannic, in which the atom is quadriva- 
lent. These are of importance to the chemist, but of little inter- 
est to the physician. 

LEAD. — Its principal ore is its sulphide (PbS), called galena. 
It is a soft, heavy blue metal, 132 very slowly acted upon by most 
substances ; hence used to make water-pipes and vessels that are 
exposed to corrosive liquids. 

Water containing nitrates or nitrites (from organic matter) 

1 ' 2 Heat some litharge on charcoal with the reducing flame of the blow- 
pipe, and note globules of metallic lead, and the physical properties of the 
metal. 



PART I. INORGANIC CHEMISTRY. &$ 

dissolves lead slightly • but if it contains carbonates or sulphates, 
the lead is protected by an insoluble coating of lead carbonate 
or sulphate. 

Lead enters into the composition of many alloys : as pewter, 
solder, shot, type-metal, etc. The quadrivalent compounds of 
lead are of so little importance that the term plumbic generally 
is applied to the bivalent compounds. 

Lead Oxide. — PbO — Litharge. — A yellow substance, found 
native ; made artificially by heating lead in the air. It is by 
treating this with the appropriate acid that most of the lead salts 
are prepared. When rubbed with oil it decomposes the glycer- 
ylic ethers and combines with the fatty acids to form lead soaps, 
one of which, the oleate, is lead plaster, e?nplastrum plumbi, U. 
S. P. 

Lead Dioxide, ox puce lead, is a dark-brown powder, 1- ^ 3 forming 
one of the constituents of red lead (Pb-A or 2PbO.PbO,). m 

Prepared by treating red lead with nitric acid to dissolve out 
the PbO. 

Lead Nitrate — Pb(K0 3 )>. 

Made : PbO - 2HNO3 = Pb(N0 3 ), + H,0. 

Ledoyen's disinfectant fluid was a solution of Pb(N0 3 )- 2 (one 
drachm to the ounce), but is no longer officinal. It corrects 
fetid odors by precipitating H 2 S and NHJHS. 

Lead Acetate— Pb(C 2 LLA),, or PbAc — Sugar of lead™ 

Made : PbO + 2HAc = PbAc 2 4- H 2 0. 

Used in medicine more than any other lead salt. Its solution 
will dissolve considerable quantities of PbO, forming the solution 

,M Onto I Gm. of red lead in a test-tube pour 5 Cc. of dilute HXO ; , and 
note that the acid attacks and dissolves only the PbO, leaving the Pb0 2 as a 
dark brown powder. 

131 Mix a little dry PbO., with pulverized sugar and note that when the 
pestle rubs hard against the side of the mortar, the sugar is oxidized by the 
PbO., and takes fire. 

U3 Heat 2 Gm. of litharge with 5 Cc. of acetic acid and filter. Allow a few 
drops of the filtrate to evaporate on a watch crystal and note the colorless 
prismatic crystals of " sugar of lead." 



84 ESSENTIALS OF CHEMISTRY. 

of the sub acetate of lead, the liquor plumbi sub ace 'talis , U. S. P., 
Goulard's extract. This is a basic acetate and is sometimes 
called vinegar of lead. It is astringent, and, like all the lead salts, 
sedative. Much used as a topical application in erysipelas, acute 
eczema, and other skin affections ; and diluted {lead water), it is 
used in conjunctivitis and other mucous inflammations. 

The following insoluble salts may be made by precipitation 
from solutions of the preceding soluble ones : l:56 

Lead Chloride — PbCl 2 . — Made : Soluble lead salt added to a 
soluble chloride ; e. g., PbAc 2 + 2HCI = PbCl 2 + 2HAc. Slightly 
soluble in warm water, but in cold it is always precipitated from 
solutions of moderate strength ; hence classed with HgCl and 
AgCl as one of the three insoluble chlorides. 

Lead Sulphate — Pb*30 4 . — Forms as a white precipitate when- 
ever a solution of a lead salt is added to a sulphate solution, 
thus : 

PbAc 2 + ZnS0 4 = PbS0 4 + ZnAc 2 . 

Lead Carbbnate — PbCO s — White Lead. 

Made: PbAc 2 + Na 2 C0 3 = PbCO s + 2NaAc. 

Commercially, it is made by some modification of the old Dutch 
method, which consists in covering sheets or bars of lead with the 
refuse of the wine-press and barn manure. The acetic fumes from 
the grape husks attack the lead, forming lead acetate, which is 
decomposed by the carbonic acid (C0 2 4- H 2 0) from the manure. 
The acetic acid thus liberated combines with another portion of 



186 Now test this filtrate for lead, by adding to successive portions the fol- 
lowing solutions, each containing a negative radical capable of forming an in- 
soluble compound with Pb : 

Sulphuric Acid. (PbAc, 4- H 2 S0 4 = 2HAc -f PbS0 4 ) white precipitate. 

Hydro sulphuric Acid. (PbAc 2 -f H 2 S == 2HAc + PbS) black precipitate. 

Sodium Carbonate. (PbAc 2 -f- Na 2 C0 3 = 2HAc -f PbC0 3 ) white precip- 
itate. 

Potassium Iodide. (PbAc 2 -f- 2KI = 2HAc 2 + Pbl 2 ) yellow precipitate. 

Potassium Chr ornate. (PbAc 2 -f K 2 Cr0 4 = 2H Ac 2 + PbCr0 4 ) yellow pre- 
cipitate. 



PART I. INORGANIC CHEMISTRY. 85 

lead, which is again precipitated by the carbonic acid, and thus 
the process continues until all the lead is consumed. 

Used for painting, but blackens when air contains ELS. 

Lead Sulphide — PbS — is formed as a black precipitate when- 
ever a lead solution is treated with a soluble sulphide, as ELS or 
NH.HS, 

Lead Iodide — PbL. — A bright yellow precipitate on adding a 
soluble iodide to a lead solution ; as, 

PbAc 2 + 2KI = 2KAc + Pbl 2 

Lead Chromate — PbCr0 4 . 

Made : PbAc, + K 2 CrO, = PbCrO, + 2KAc. 

Under the name of chrome yellow it is used in painting. Ot 
late it has been used to color food products. 

Tests for lead consist mainly in forming precipitates of the fore- 
going insoluble compounds. 

Physiological.— All the lead compounds are poisonous. Acute 
poisoning sometimes occurs from the ingestion of a single large 
dose of a soluble lead salt. The symptoms are those of gastric 
irritation. Treatment: Give MgSO. to form the insoluble PbS0 4 . 

The chronic form of lead intoxication, painter's colic, is true 
poisoning, and is produced by the continued absorption of min- 
ute quantities of lead by the skin of those handling it, and by the 
lungs and stomachs of those living in painted apartments, or 
using food and drink from leaden vessels or soft and contami- 
nated water conveyed through lead pipes. There is impairment 
of digestion, constipation, blue line along the edge of the gums, 
colic and paralysis, especially of the extensor muscles. Lead 
once absorbed is eliminated very slowly, having combined with 
the albuminoids, a combination which is rendered soluble by the 
administration of iodide of potassium. 

The treatment for chronic lead-poisoning is to give MgS0 4 , for 
the double purpose of overcoming the constipation and precipi- 
tating any lead remaining unabsorbed in the alimentary canal ; 
also KI to promote the elimination of that which is combined 
with the albuminoids. Alum is a favorite treatment, seeming to 



86 ESSENTIALS OF CHEMISTRY. 

perform all accomplished by both the MgS0 4 and KI. The par- 
alyzed muscles must be treated with electricity, so that when the 
lead is eliminated and the nerve influence returns, it may not find 
them degenerated past redemption. 

Potassium Group. 

(Hydrogen H i ) 

Lithium Li 7 

Ammonium (NH 4 ) 18 

Sodium (Natrium) Na 23 

Potassium (Kalium) K 39.1 

Rubidium Rb 85 

Cesium Cs 133 

Group Characteristics. — Univalent ; very electro-positive (ex- 
cept H), so that when combined, unless it be with a strongly 
electro-negative (acidulous) radical, they form very alkaline com- 
pounds. The positive affinities, as in the other groups, increase 
with the atomic weights. All their compounds are soluble. 

LITHIUM. — Sparingly but- widely distributed in nature, es- 
pecially in the waters of certain springs. Lightest of the solid 
elements. Its salts closely resemhle those of sodium. 

Physiological. — Lithium urate being by far the most soluble com- 
pound of uric acid, salts of lithium, especially the very soluble 
citrate and the less soluble carbonate/' 7 are given to gouty per- 
sons to promote the elimination of uric acid, which accumulates 
in that disease. But much of the lithium seems to go to neu- 
tralizing the acid sodium phosphate instead of combining with 
the uric acid. 

Test. It colors the flame a beautiful carmine red ; 138 its phos- 
phate is insoluble in presence of ammonium hydrate. 139 

117 Lithium. Tests. Note the taste, reaction and slight solubility (1 in 80) 
of Li 2 C0 3 ; dissolve a little in HO, avoiding excess of acid, and test the 
solution . 

138 Fla?Jie. Dip end of platinum wire in solution and place in edge of the 
Bunsen flame and note the carmine-red. 

1{9 Phosphate. Into a test-tube pour some Na 2 HP0 4 solution and half as 
much NH 4 HO and then a few drops of the Li solution, and warm slightly. 
Note white precipitate of Li 2 HP0 4 . 



PART I. — INORGANIC CHEMISTRY. 87 

AMMONIUM. — When ammonia gas (NH 3 ) combines with an 
acid, it appropriates the basic hydrogen of the acid and forms a 
salt in which NIl 4 is the positive radical ; e. g.: 

NH 3 — HC1 = NH 4 C1, corresponding to KC1 or XaCl; 
NH 3 -HHO=XH 4 HO, corresponding to KHO or NaHO; 
NH 3 — HNOg =NH 4 N0 3J corresponding to KNO a or NaNO s ; 

2XH, - H 2 S0 4 = (NH 4 ) 2 S0 4J corresponding to K,,S0 4 or Xa,S0 4 . 

This radical (NH 4 ) plays the role of a metal, like K and Na, 
and is called Ammonium. Does not exist uncomblned, although 
Wey] claims to isolate it as a dark-blue liquid metal. 140 We can 
obtain it as amalgam by the reaction between sodium amalgam 
and ammonium chloride. 141 

Ammonium Hydrate — XH 4 HO — Caustic Ammonia — is formed 
in solution whenever ammonia gas (NH 3 ) dissolves in water, 
thus: NH 3 + H 2 = NH 4 HO. It has been already stated that 
the aqueous solution of a fixed substance is called a liquor ; of a 
volatile substance, an aqua. In like manner alcoholic solutions 
of fixed substances are called tinctures, and of volatile, spirits. 
There are four U. S. P. solutions of ammonia : 

Aqua ammonia jo per cent. 

Aqua ammonia fortior 28 " 

Spiritus ammonia 10 u 

Spiritus ammonia aromaticus. " *' 



ll0 XOTE. — The siipposed free ammonium. Sodio-ammonium is prepared 
by heating sodium in a sealed tube with ammcnia gas. This is in turn 
heated with ammonium chloride in a sealed tube. A dark -blue liquid, with 
metallic lustre, is obtained, but soon decomposes into ammonia gas and hydro- 
gen. 

141 To some mercury in a test-tube add sodium, small bits at a time. On 
this sodium amalgam pour a strong solution of ammonium chloride. wSodium 
chloride and ammonium amalgam are formed. 

(Xa + Hg) — NH 4 Cl = NaCl — (XH, — Hg). 
The ammonium amalgam swells up and soon decomposes — (NH 4 — Hg) = 
XH 3 - H-f Hg — the gaseous XH, and hydrogen escape, and only the mer- 
cury remains. 



88 ESSENTIALS OF CHEMISTRY. 

In each of these solutions NH 4 HO exists, but has never been 
isolated, because, whenever we attempt to evaporate the water or 
alcohol, the NHJHO decomposes into NH 3 4- H 2 0. 142 Ammo- 
nium hydrate is very alkaline. 

Ammonium Hydrosulphide — NH 4 HS — occurs in decomposing 
nitrogenous, sulphurized organic bodies. Made by saturating a 
solution of NH4HO with H 2 S. A yellowish solution; used as a 
test reagent. 

Ammonium Carbonate — (NH 4 ) 2 C0 3 . — Ammonii Carbonas, U. 
S. P. 143 — Sal volatile — is prepared by heating a mixture of NH 4 C1 
and chalk (CaC0 3 ) up to the temperature at which (NH 4 ) 2 C0 3 
would be volatilized, when the following reaction will occur. 144 

2NH 4 C1 + CaCG 3 = CaCl 2 + (NH 4 ) 2 C0 3 

(See Volatility, page 33.") Very prone to absorb C0 2 from the 
atmosphere and become bicarbonate unless NHJiO be added. 

Other salts may be made by adding the appropriate acid to 
the carbonate or hydrate of ammonium. If we use the carbonate 
we can tell when acid enough has been added by the cessation of 
effervescence. If the hydrate is used there is no effervescence, 
and our only guide is the point at which the solution becomes 
neutral in reaction. This is determined by the use of test papers. 
These are made of white, unsized paper, steeped in a blue vegeta- 
ble pigment called litmus, which is reddened by acids and restored 
to its blue by alkalies. 

Physiological — The hydrate and carbonate are alkaline irritants, 

^Ammonium Tests. NH 4 HO. Pour aqua ammonise into a test-tube and 
note (<z) the odor and alkalinity of the escaping NH 3 , (3) white fumes of 
NH 4 C1 when a glass rod moistened with HC1 is brought near the mouth of 
the tube, and (c) that after boiling, the water has become almost tasteless and 
neutral. 

113 The officinal dry salt consists really of ammonium bicarbonate and car- 
bamate, but the latter on dissolving in water becomes normal ammonium car- 
bonate. 

lu Carbonate. Heat a mixture of chalk (CaC0 3 ) and sal ammoniac 
(NH 4 C1) and hold an inverted beaker over the mouth of the test-tube. Note 
the sublimate in the beaker and its odor, taste, solubility and reaction. 



PART I.— INORGANIC CHEMISTRY. 89 

like the corresponding K and Na compounds, though in less de- 
gree. They moreover give off NH 3 , which, though irritating to 
the respiratory tract, is a valuable stimulant in fainting fits, etc. 
Two drachms of aqua ammoniae have killed. The treatment, as 
for all alkalies, is to give a dilute acid or some oil. 

Tests. — (1) An ammonium salt warmed with liq. potassse gives 
off NH 3 , recognized u '° (a) by its odor, (b) its forming a white cloud 
of NH 4 C1 when a glass rod dipped in the HC1 is held over the 
vessel, and (c) its changing moist red litmus to blue. (2) Heat 
the dry ammonium salt and it volatilizes. 146 (3) Platinic chlor- 
ide 147 gives a creamy yellow precipitate, and (4) Nessler's' 48 reagent, 
a brown coloration. 

SODIUM. — Occurs very abundantly in sodium chloride, or 
common salt, and from it almost all the other sodium com- 
pounds are now obtained, instead of from the ashes of sea-weeds 
as formerly. Sodium resembles potassium very closely, except 
that sodium is a little less positive and its compounds manifest 
the alkaline tendency a little less strongly. As a rule the sodium 
salts tend to effloresce and the potassium salts to deliquesce on 
exposure to the air. But the compounds of the two metals are 
so alike in their preparation, properties and uses that the physi- 
cian's or chemist's choice between them is usually determined 
by such considerations as economy, convenience, solubility, etc. 
Hence of the sodium compounds we will notice only a few as being 
of particular importance. 

Sodium Chloride. — NaCl, or common salt, is very abundantly 



145 NH^ from Salts. To an ammonium salt in a test-tube add KHO solu- 
tion and warm. Xote the NH 3 evolved and recognize it as above suggested. 

146 Sublimation. Heat some impure NH 4 C1 in a large test-tube and note 
that it sublimes and collects in pure white masses in the upper part of the tube. 

U7 Platinic Chloride. To a few drops of ammonium salt on a microscope 
slide or watch-glass add one drop of HO and a drop of PtCl^ (an expensive 
reagent), and note the yellow precipitate of PtCl^NH^Cl. 

J48 Xessler's. To an extremely dilute solution of an ammonium salt add a 
few drops of Nessler's reagent and note the brown coloration and the great 
delicacy of the test. 

7 



90 ESSENTIALS OF CHEMISTRY. 

and widely distributed, occurring in most animal and vegetable 
tissues, and in all natural waters, especially sea water. Where 
arms of the sea and salt lakes have evaporated hrough ages, de- 
posits of rock salt are found, often of vast extent, as at Stassfurt in 
Germany and Petite Anse in Louisiana. When pure it is not 
hygroscopic, though common salt is usually slightly deliquescent 
on account of the presence of magnesium salts. 

Sodium Dioxide. — Na 2 2 — "peroxide of sodium" is a yellow- 
ish, very caustic solid and has recently assumed commercial im- 
portance as an oxidizing, bleaching and disinfecting agent, for 
with water it yields about 20 per cent, of oxygen (Na 2 2 + H 2 = 
2NaH0 4-0) and with dilute acids produces hydrogen dioxide 
(Na 2 2 + 2HCI == 2NaCl + H 2 2 ) . 

Sodium Bicarbonate — NaHC0 3 — baking soda. Effervescing 
mixtures such as Seidlitz powders and baking powders generally 
consist of sodium bicarbonate and potassium bitartrate mixed dry. 
In some cheaper varieties of baking powders alum and acid cal- 
cium phosphate are used instead of the cream of tartar. On the 
addition of water the following reaction occurs with evolution 
of C0 2 : 

NaHC0 3 + KHQH 4 6 = NaKC 4 H 4 6 -f H 2 + C0 2 . 

Sodium Sulphate — Na 2 S0 4 .ioH 2 or Glauber's Salt and 
Sodium Phosphate — Na 2 HP0 4 — are useful saline purgatives ; and 
Sodium Sulphite — Na 2 S0 3 — is used in preventing fermentation 

and as a reducing agent in photography. 

Tests. — No good precipitant ; for all the compounds of sodium 

are soluble. However, the strong yellow color it gives a flame is 

a very delicate test ; in fact, often annoyingly delicate, for it 

shows traces of sodium in almost everything. 

POTASSIUM occurs only in compounds. Prepared by heating 

one of its oxygen compounds with charcoal in an iron retort 

(K 2 C0 3 + 2C = 3CO + K 2 ). The metallic K distills over and is 

condensed in a flat receiver. 

Physical Properties. — Soft as wax ; lighter than water ; silvery 

lustre when freshly cut, but quickly tarnishes. 



PART I. — INORGANIC CHEMISTRY. 



91 



Chemical Properties. — Intensely electro-positive ; hence it pos- 
sesses great affinity for the non-metals; 149 takes O from H 2 0, 150 
even as ice,' 51 setting fire to the escaping H, and giving the flame 
the violet color characteristic of K (Fig. 38). 



Fig. 37. 



Fig. 38. 





Potassium Carbonate. — K 2 C0 3 . — Obtained as an impure solu- 
tion ("lye") by lixiviating the ashes of plants, especially forest 
trees. This, evaporated to dryness, forms " concentrated lye " or 
"potash." This in turn when purified forms "pearl-ash," which 



Fig. 39. 



Kf 



C(k 




is further purified for medicinal use. Sometimes made by burn- 
ing cream of tartar and lixiviating the residue ; hence called salts 
of tartar. A white semi-crystalline or granular powder. C0 3 



Potassium. Metal. Let the instructor ( l49 ) inflame a bit of metallic K by 
lowering into a jar of chlorine, Fig. 37, or ( l5() ) make an explosion by warming 
it with iodine or dropping it into bromine, taking care to cover the experiment 
with a bell jar. 151 Load a strong toy cannon with gun-powder, lay a small bit 
of K in the fuse and touch off with a piece of ice. Fig. 39. 



92 ESSENTIALS OF CHEMISTRY. 

being a weakly acidulous (negative) radical, K 2 C0 3 is very alka- 
line, even caustic. 152 

Acid Salts. — Salts are formed by a metallic radical displacing 
the basic H of an acid. If all the H is displaced, the result is a 
normal salt, as, H 2 S0 4 4 K 2 — K 2 S0 4 ,-h H 2 . But if part of the 
basic H of the acid remains, it is called an acid salt, as H 2 S0 4 + 
K^KHS0 4 +H. Sometimes acid salts are called "bi" salts, 
because the proportion of the acidulous radical to the basylous is 
twice as great as in the normal ; e. g., KHS0 4 is called potassium 
bisulphate, because the proportion of the acidulous radical S0 4 to 
the basylous radical K is twice as great as in the normal sulphate, 
K 2 S0 4 . 

Potassium Bicarbonate — KHCO3. — Although an acid salt in 
constitution, it is alkaline in reaction, on account of the weakness 
of its acidulous radical. Made by passing C0 2 into a solution of 
K 2 C0 3 . The reaction is as follows : — 

K 2 CO s + H 2 + C0 2 = 2KHC0 3 . ' 

Potassium Bitartrate — KH(C 4 H 4 6 ) or KHT — Cream of 
Tartar. — Prepared similarly to the above, by adding tartaric acid 
to a solution of the normal tartrate, thus: K 2 T+H 2 ^2KHT. 
It exists naturally in grape juice, and, being insoluble in an alco- 
holic menstruum, is precipitated on the sides of the wine casks 
whenever vinous fermentation sets in. This is its commercial 
source. 

Other Salts. — Most salts of K are made by treating the car- 
bonate with the appropriate acid, e. g. : — 

The chloride— K 2 CO, + 2HCI = 2KCI + H 2 + C0 2 . 
The sulphate— K 2 CO, + H 2 S0 4 = K 2 S0 4 + H 2 + C0 2 , etc. 

The decomposition is attended with an effervescence of C0 2 . 
It is the formation of this volatile compound that determines the 
reaction. (See Volatility, page 33.) 

152 Let the student drop a bit of K into a beaker one-fourth full of water, 
Fig. 38, and cover quickly. Note (a) that the liberated hydrogen ignites in- 
stantly and burns with a violet flame, exploding at the close; (b) that the 
water has a soapy taste and feel; (c) that it is alkaline, and (d) HC1 neutral- 
izes it without effervescence, showing absence of carbonate. 



PART I. — INORGANIC CHEMISTRY. 93 

But the following salts are not made in that way; — 
Potassium Hydrate — KHO — Caustic Potash — may be made 
experimentally by the reaction of metallic K on water, thus : — 

H 2 + K = KHO 4-H. 

But made in the shops by boiling K 2 C0 3 with slacked lime, 
thus :— 153 

K,C0 3 -f Ca2HO = CaC0 3 - 1 - 2KHO. 

The insoluble CaC0 3 (chalk) sinks to the bottom, and the 
KHO dissolves in the supernatant liquid, which when clear is 
poured off (decanted). This watery solution, if of proper 
strength (5 per cent.), forms " Liquor fotasscv, U. S. P." If this 
solution is evaporated to a syrupy consistence and poured into 
moulds, it forms the stick caustic potash. KHO is very alkaline, 
and a powerful caustic. 151 

Exposed to the air it absorbs C0 2 and forms the carbonate : — 

2KHO - CO, = K,C0 3 - H 2 0. 
Potassium Iodide — KI : — 

6KHO -i- 61 = 5KI - KIO a — 3H 2 C 

The color disappears because the I goes to form colorless salts. 
The iodate' 58 being a disagreeable and otherwise undesirable con- 
tamination, the mixture should be strongly heated to decompose 
the iodate (KI0 3 = KI - O a ) leaving only KI. The addition of 
charcoal facilitates the removal of the oxygen. 

Potassium Bromide — KBr — may be made like the foregoing. 

15j KHO. — Boil 100 Gm. of KX0 3 in water in an iron dish and add lime 
until a sample of clear liquid does not effervesce with an acid. Allow the 
CaC0 3 to subside and then decant the clear solution of KHO. 

154 Causticity. Add portions of this KHO solution to three test-tubes. 1 :5 
To one add some animal matter as wool and boil, noting that the wool is soon 
dissolved; l56 to another add some vegetable fibre as cotton or paper, and 
note that the fibre swells up arfd after considerable boiling dissolves; lhl in 
the third boil some fat and note that the fat is soon emulsified and dissolved 
forming soap, and that it lathers on shaking and that when HC1 is added the 
fat-acids separate and float on in an oily-looking layer. 

158 Iodate. To detect the presence of KI0 3 in a commercial specimen of 



94 ESSENTIALS OF CHEMISTRY. 

Potassium Nitrate — KN0 3 — niter, saltpeter, occurs in nature 
but so sparingly that until the introduction of the cheaper Chili 
saltpeter (NaN0 3 ) it was produced in large quantities artificially 
on the so-called saltpeter plantations by mixing wood ashes and 
manure in heaps and allowing them to lie for several years and 
slowly decay. In the presence of air, moisture and certain nitri- 
fying organisms the nitrogen of the manure is oxidized and com- 
bines with the potassium in the ashes forming KN0 3 , which is 
separated by lixiviation or "leaching." It is often noticed as a 
white efflorescence on compost-heaps. It is used in medicine 
and pharmacy ; and very much in the arts, especially in the manu- 
facture of gunpowder and fireworks, on account of the ease with 
which it gives up its oxygen to combustible substances. 161 

Sodio- Potassium Tartrate — NaKT — Rochelle Salt. — A neutral 
salt made by boiling acid potassium tartrate with sodium bicar- 
bonate. 

KHT + NaHC0 3 = NaKT + H 2 + C0 2 . 
This is the reaction that occurs in bread -making with cream of 
tartar baking powders. 

Potassium Hypochlorite — KCIO. — Made by passing chlorine 
into a cold solution of KHO. Yields free chlorine. The ordin- 
ary bleaching solutions (Labarraque's Solution or Javelle water) 
are impure solutions of the hypochlorite of sodium or of potassium. 

Tests for Potassium. — (i) If the suspected solution is concen- 



KI : boil a grain of starch in water in a test-tube; add a crystal of the sus- 
pected KI and then a few drops of tartaric acid. If KI0 3 be present iodine 
is liberated and strikes a blue with the starch. 

159 Other Hydrates. Add a few drops of the KHO to test-tubes containing 
respectively, CaCl 2 , FeS0 4 , and CuSCX. Note the appearance of the precipi- 
tated hydrate of each metal and that they all dissolve when acidulated with 
HNO tS or other strong acid. 

160 Carbonates. Refill each test-tube and repeat the preceding experiment 
except using K 2 C0 3 instead of KHO solution. Note appearance and be- 
havior of the respective carbonates. 

lftl Nitrate. Carefully neutralize 5 gm . of K 2 C0 3 solution with HNO H , 
stopping when effervescence ceases; dip a strip of paper in it and. ignite it 
when dry. Note that it burns like tinder, 



PART I. — INORGANIC CHEMISTRY. 95 

trated, add H 2 T and get a precipitate of KHT. 162 (2) Platinic 
chloride (PtClJ gives a yellowish precipitate. 165 But the PtCl 4 is 
very costly, and all the potassium compounds so soluble that the 
above tests are but little used. The most convenient is the (3) 
flame test; dip 16 ' the end of a clean platinum wire in the sus- 
pected solution, and hold in the colorless Bunsen or alcohol flame 
and notice the violet color. 

CESIUM AND RUBIDIUM. — Rare metals, occurring in 
small quantities with potassium. Discovered in i860 by means 
of the spectroscope, and named from the colors of their lines in 
the spectrum ; cazsius, sky blue, and rubidus, dark red. Of no 
medical interest as yet. 
ACIDIMETRY AND ALKALIMETRY. 

Volumetric Analysis depends on the fact that all substances 
combine in certain definite and fixed proportions — elements in 
the proportions of their atomic weights and compounds in the pro- 
portions of their molecular weights. 

KHO KC1 HO 

" h 39.1 + 1 4- 16 39.1 - r 35.5 + 1 + 16 



36.5 56.1 74.6 18 

So that by measuring the quantity of one substance entering 
into a complete reaction we can readily estimate the others. For 

162 Bitartrate Test. To a solution of a K salt add a strong solution of tar- 
taric acid, first adding a little alcohol to make the more delicate. Note the 
precipitate of sodium potassium tartrate. 

l& Platinic Chloride Test. To a few drops of a potassium solution on a 
glass slide or watch glass add a drop of alcohol and then a drop of PtCl 4 , 
and note creamy precipitate of PtCL2KCl. 

164 Flame Test. Dip tip of a platinum wire into a potassium solution and 
hold it hi the Bunsen flame, and note the delicate violet color, best observed 
through a piece of blue glass to intercept any yellow from accidental admix- 
ture of sodium salt. 

165 Analytical. To determine whether a salt be a compound of K, Xa. 
NH 4 , or Li, heat samples of each; the one that volatilizes is the salt of NH 4> 
Confirm this by boiling with KHO and getting the odor of ammonia. To the 
other three salts apply the flame tests, getting the violet for K, yellow for Na, 
and carmine for Li. 



96 



ESSENTIALS OF CHEMISTRY. 



convenience these measuring (volumetric) solutions are each 
made by dissolving in a liter (iooo Cc. or grams) a number of 
grams equal to the molecular weight of the substance as com- 

Fig. 40. Fig. 42. 



Fig. 41. 

Q 





pared to one atomic weight of hydrogen, counting in of course 
the water of crystallization, if any, entering into the molecule. 
So a certain volume of one solution is exactly the chemical 



PART I. INORGANIC CHEMISTRY. 97 

equivalent of the same volume of another solution. Such solu- 
tions are called normal volumetric solutions. Whenever a more 
dilute solution is desired, it is made one-tenth or one-hundredth 
of the normal strength and called a decinormal or centinormal 
solution. The necessary apparatus consists only of a graduated 
pipette Pig. 40, a liter-flask Fig. 41, and a burette Fig. 42. A 
burette is a long narrow tube with some sort of a stop-cock at its 
lower end and with accurate graduations by which the amount of 
liquid drawn ofT can be accurately read. 

To estimate the quantity of an alkali or of an acid in a specimen, 
a certain volume of it is measured out and a few drops added of 
an " indicator," usually a dye-stuff that will change color at the 
point of neutralization and mark the end of the reaction. Then 
after first noting the height in the burette of the test solution, 
this is added cautiously, especially towards the end, with con- 
stant stirring until the color changes (the end of the reaction). 
The amount of the test solution used from the burette is read off, 
and from this the quantity of the opposite substance in the speci- 
men is easily calculated. 166 

Calcium Group. 

Calcium, Ca 40 

Strontium, . . ' Sr 87.5 

Barium, Ba 137 

Bivalent ; their oxides and hydrates are very alkaline, but of an 
earthy character. Their positiveness or basicity is in the order of 
the atomic weights. Their carbonates are decomposable by heat 
and insoluble in water, unless it contains FLCO3 in solution. 
Their sulphates decrease in solubility from the slightly soluble 
calcium sulphate to the extremely insoluble barium salt. 



166 Exercise. Measure into a beaker 5 Cc. of KHO solution and add a drop 
or two of phenolphthalein, and note that it instantly turns pink. Now add the 
acid test solution very slowly and with constant stirring until the pink sud- 
denly disappears. Then multiply the number of cubic centimeters cf the test 
solution used by the factor for KHO (equivalent in icoo being .0561). In a 
similar way "titrate" solutions of HC1, etc., for practice. 



98 ESSENTIALS OF CHEMISTRY. 

CALCIUM. — Never free, but its compounds are very abundant, 
as limestone, 167 gypsum, etc. Calcium salts are necessary to animal 
life, the teeth and bones consisting mainly of calcium phosphate. 

Calcium Chloride — CaCl 2 . 

Made : W8 CaCO a + 2HCI = CaCl 2 4= H 2 + CO,. 

A white salt ; very avid of water and deliquescent ; used to dry 
gases. 

Calcium Carbonate — CaC0 3 . — Abundant as limestone, marble, 
corals, chalk, and shells of the Crustacea, mollusks, etc. Chalk 
consists of microscopic shells. Precipitated chalk is made 169 by 
adding a soluble carbonate to a soluble calcium salt, as : — 
Na 2 C0 3 -\ CaCl 2 = 2NaCl + CaC0 3 . 

The precipitate (CaC0 3 ) may be separated from the NaCl in 
solution, by — 

(a) Filtration. — Pouring the mixture into a cone of filter paper 
placed in a funnel, when the water with the dissolved salt will 
pass through, leaving the insoluble portion (the precipitate) on 
the filter, (b) Decantation. — Allowing the precipitate to settle 
to the bottom, and pouring off the clear fluid. In either case the 
precipitate may be freed from any remaining NaCl by adding 
pure water and repeating the process. CaC0 3 is slightly soluble 
in the presence of free H 2 C0 3 . 

Calcium Oxide — CaO — Lime, quicklime; calx, U. S. P. — A 
white solid ; made by heating limestone m in furnaces called kilns. 



CALCIUM. 

167 Flame. Dip a little lump of marble into HC1 and hold it in the Bunsen 
flame — a red flash. 

168 To an excess of chalk in a test-tube add dilute HC1. Note effervescence 
of C0 2 , and when it ceases filter or decant. 

169 To the clear solution add some carbonate (as of K, Na or NH 4 ) and note 
white " precipitated chalk." 

170 In a side-neck test-tube with delivery tube generate C0 2 from HC1 and 
lump of marble. Conduct the gas into lime-water. Note that CaC0 3 is at 
first precipitated and afterwards redissolved by the C0 2 . 

171 Heat a little lump of marble white-hot. Note that it loses its crystalline 
appearance, and becomes CaO. 



PART I. — INORGANIC CHEMISTRY. 99 

CaC0 3 -= CaO + C0 2 . 
When water is added to CaO there is a violent chemical union, 
great heat is evolved, and a hydrate is formed 17 ' 2 thus : — 
CaO +- II 2 = Ca(HO) 2 . 

Calcium Hydrate — Ca2HO — Slacked lime. — A white odorless 
powder ; very slightly soluble in water, less than one grain to the 
ounce, but enough so to give "lime-water " {liquor calcis, U. S. P.) 
a decidedly alkaline taste and reaction. The presence of sugar 
greatly increases its solubility (liq. calcis saccharatus, Br.). 

Chlorinated Lime — Chloride of lime, bleaching powder, calx 
chlorata, U. S. P. — is a mixture of chloride of calcium (CaCL) 
and calcium hypochlorite (CaCIO 2 . It is made by passing 
chlorine gas over slacked lime until it ceases to be absorbed. It is 
white, moistens on exposure to the air, absorbing C0 2 and giving 
off CI. It is employed as a source from which to get a gradual 
supply of chlorine for disinfecting and bleaching purposes. 

Calculi Sulphate — CaS0 4 173 — occurs native as gypsum, which, 
when heated, loses its water of crystallization 171 and forms a white 
amorphous powder called plaster-of -Paris. If this plaster be 
mixed with water enough to form a creamy liquid, it will re-crys- 
talize or "set" into a hard compact mass. 175 Much used in sur- 
gery to make casts to hold broken limbs in position. Very 
slightly soluble in water. 176 

172 Let the CaO cool, and then drop it into a test-tube and add a few drops 
of water. Note that it combines with the water, swells up and the tube feels 
hot. 

173 To an inch (about 5 Cc.) of CaCl 2 solution add a few drops of MgS0 4 
and note white precipitate of CaS0.2H 2 0. 

174 Heat carefully in a test-tube a lump of natural gypsum (CaSO r 2H.,0) or 
fragment of an old plaster cast. Note that the water of crystallization escapes 
and condenses on the sides of tube and the gypsum loses its crystalline char- 
acter. 

175 Mix some plaster of Paris into a paste with water and pour into a pill 
box; press into the surface a greased coin or key. After it " sets" remove the 
coin or key and the pill box, and note the cast and the impressions. 

176 To water that has been standing on CaS0 4 in a test-tube add BaCl 2 and 
note white precipitate of BaS0 4 , showing the extent to which CaS0 4 dissolves 
in water. 



tf& 



IOO ESSENTIALS OF CHEMISTRY. 

Calcium Phosphate — Ca 3 (P0 4 ) 2 . 178 It is the most abundant 
mineral ingredient of the body ; is in every tissue and fluid, especi- 
ally the teeth and bones, to which it gives hardness and rigidity. 
A white tasteless powder, soluble in dilute acids. Dissolved by 
lactic acid, it is given as syrupus calcii lactophosphatis, U. S. P., 
in scrofula, rickets, and other diseases of defective nutrition. 

Calcium Oxalate— CaC 2 4 , or CaOx — occurs in the juices of 
some plants and in the urine. Obtained as a fine white crystal- 
line powder when a soluble oxalate is added to a calcium solu- 
tion. 177 Insoluble in water or acetic acid, but soluble in the 
mineral acids. 

Calcium Carbide — CaC 2 . — This new compound, 179 important 
commercially as a cheap source of the valuable illuminant acety- 
lene and interesting chemically as bridging over the chasm between 
inorganic and organic substances, and enabling us to make an 
organic compound directly from the elements, w T as discovered 
almost accidentally a few years ago. A young man was operating 
an electric furnace in a small aluminum works on the little river 
Spray, in North Carolina, and happened one day to throw in 
some lime and coal. 'Instantly they fused into a dark lustrous 
mass, which he soon threw into the mill-pond. The vigorous 
bubbling of gas which ensued completed the discovery of a new 
and cheap method of manufacturing acetylene, (CaC 2 + 2H 2 = 
Ca(2HO) 2 4- C 2 H 2 ). Acetylene is exceedingly rich in carbon, 
and burns with a smoky flame, but with a proper admixture of air 
gives a light of intense whiteness and power. 

Hard Waters are such as contain mineral matters, especially 
calcium (lime) compounds. Often water, in passing through the 
soil, becomes highly charged with carbonic acid, and dissolves 



177 Repeat preceding, adding oxalic acid (H 2 C 2 4 ), and note white precipi- 
tate of CaC 2 4 , insoluble in alkalies and weak acids but soluble in strong HC1. 

178 To a calcium solution add Na.,HP0 4 and note white precipitate of 
Ca 3 (POJ 2 , soluble even in weak and dilute acids. 

179 Acetylene. Into a beaker of water drop a small lump of CaC 2 and note 
a copious, white precipitate of Ca(2HO) 2 and a rapid bubbling of C. 2 Ii. 2 , which 
is easily recognized by its pungent odor and bright smoky flame when ignited. 



PART I. — INORGANIC CHEMISTRY. IOl 

considerable amounts of CaCO s , and is hard. This is called 
temporary hardness, because on exposure or boiling, the carbonic 
acid is driven off, the CaC0 3 is precipitated, and the water be- 
comes soft. The solubility of CaSO^ does not depend on the 
presence of carbonic acid, and so boiling will not precipitate it. 
So water impregnated with CaSO^ is said to be permanently hard. 
Drinking-water should contain a small quantity of lime ; but very 
hard water impairs digestion. Hard water is unfit for washing, 
because the soluble alkali soap reacts with the lime salt to form 
an insoluble lime-soap. 180 

STRONTIUM. — This is a yellowish lustrous metal, occurring 
never free but always in compounds resembling and analogous to 
those of calcium, but far less abundant. Through the studies of 
Laborde, See, Solomon and others, strontium has recently come 
to be recognized as the best base for iodine, bromine, salicylic 
acid, etc., as it is non-toxic, sedative to the stomach and is said 
to have a peculiar nutritive influence. Since strontium colors the 
flame red 182 its salts, especially the nitrate, are used in pyrotechny 
to make "red fire." 

BARIUM. — Of little interest to the medical student, except 

la0 Half fill two test-tubes, one with distilled and the other with hard water; 
add to each a few drops of soap solution and shake thoroughly. Note that 
the distilled water quickly " lathers " and that the liquid is felt to strike the 
glass softly; and that the hard water strikes hard and does not lather, but 
forms a precipitate or curd (calcium soap). 

181 Estimation of Hardness. To ico Cc. of the water in a clear vial add 
gradually from a burette the " standard soap solution," shaking after each 
addition and stopping when a permanent lather appears. Each Cc. of soap 
solution used represents one degree of hardness, i. e., I part of CaC0 3 in ioo,- 
ooo parts of the water. A water with not over rive degrees of hardness is 
classed as a soft water. 

lc - Strontium. Flame. Dip platinum wire into solution of Sr(N0 3 ) 2 and 
note the red color it gives the Bunsen flame. 

183 To solution of CaS0 4 in a test-tube add a strontium solution and note 
that SrS0 4 is precipitated, being more insoluble than CaS0 4 . 

184 Barium. Carbonate. Add Xa 2 C0 3 to BaCL, solution and note the white 
precipitate of BaC0 3 . 

185 Heat white-hot a lump of native BaC0 3 (witherite) ; add the resulting 
BaO to water and note that it "slakes" with evolution of heat and dissolves 
forming a solution of Ba(HO) 2 . 



102 ESSENTIALS OF CHEMISTRY. 

that its compounds are poisonous. Barium sulphate is very in- 
soluble;' 8 " hence (i) the antidote of barium is some soluble sul- 
phate, and (2) barium solutions (nitrate and chloride) are 
delicate tests for sulphates, and vice versa, (See Insolubility} 
Barium gives the flame a green color; 188 hence used (nitrate) in 
pyrotechny to make the green or Bengal light. 

Magnesium Group. 

Magnesium, Mg 24 

Zinc, Zn 65.3 

Cadmium, Cd 112 

Group Characteristics. — Bivalent ; bluish white-lustrous metals ; 
quite permanent in air, but when highly heated they volatilize 
and ignite, burning with a bluish-white light very rich in chemical 
rays. Magnesium is sometimes classed in the calcium group, but 
it is more closely allied to zinc. 

Magnesium. — Never free; abundant in magnesian limestone 
(CaC0 3 .MgC0 3 ). Asbestos, meerschaum, and soapstone are 
native silicates. Most natural waters contain its salts. Silvery- 
white metal ; burns with a brilliant white light, rich in chemical 
rays, and used in photographing caves and other dark places. 189 

Magnesium Sulphate — MgS0 4 — occurs in the waters of various 
springs, as those at Epsom ; hence often called Epsom salts. 
Made artificially from the native carbonate, thus : — 

MgC0 3 + H 2 S0 4 = MgS0 4 + (H 2 + CG 2 ). 
White, crystalline, soluble salt, of a nauseous bitter taste. It is 

186 Sulphate. To a barium solution add a soluble sulphate and note white 
precipitate of BaSO + . Let the precipitate settle, then pour off supernatant 
liquid and add HN0 3 and boil : it does not dissolve. 

187 To a barium solution add K 2 CrO + : note yellow precipitate, insoluble in 
water but soluble in nitric and hydrochloric acid. 

188 Flame. Dip platinum into a solution of BaCl 2 and note that it colors 
the flame green. 

189 Magnesium. Metal. Seize a piece of magnesium ribbon with the for- 
ceps; note its properties and then hold it in the Bunsen flame and note that 
it burns with a blinding bluish-white flame into a white powder of magnesia 
(MgOj. 



PART I. INORGANIC CHEMISTRY. IO3 

a popular purgative. The nauseous taste and gripirg may be 
obviated by adding sulphate of iron, as in Crab Orchard salts, or 
aromatics, or acids, by free dilution. 

Magnesium Citrate is the most pleasant of the saline purga- 
tives. Usually given as the liquor magnesii citratis, which is 
prepared by adding a solution of citric acid to MgC0 3 , and 
bottling immediately to retain the C0 2 - 

Magnesium Carbonate — MgC0 3 — occurs native. For medi- 
cinal purposes it is prepared by precipitation, thus : 190 

MgS0 4 — Na 2 C0 3 =s Na 2 S0 4 + MgCO s . 

Similar to chalk in its physical and in its chemical properties. 

Magnesium Oxide — MgO — Magnesia. Made like CaO, by 
heating the carbonate, 191 but is more mildly alkaline than CaO. 

MgCO a --= MgO + C0 2 . 

Insoluble and tasteless (earthy), but its alkalinity is shown by 
its turning moist red litmus paper blue when the solid MgO is 
dropped upon it. 19 " 

Magnesium Hydrate — Mg(HO) 2 . — Formed by precipitating a 
magnesium solution with potassium or sodium hydrate. Insoluble 
in water, but, like other salts of magnesium, soluble in the pres- 
ence of ammonium compounds with which they form double salts. 
Suspended in water, it is "called milk of magnesia™* 

Magnesium Phosphates. — These resemble the calcium phos- 
phates and are associated with them in the body, though in small 
quantity. The anwionio-magnesium phosphate (MgNH^POJ is 

190 To a solution of MgS0 4 add a few drops of Na 2 CO s . Note the white 
precipitate of MgCO s , which dissolves on addition of NH 4 C1. 

191 Heat white-hot a lump of dry MgC0 3 : let it cool and note that it is 
MgO ("calcined magnesia"), is alkaline to litmus and on the addition of 
acid dissolves without effervescence. 

192 with a dear glass rod rub a bit of this white powder on a bit of mois- 
tened red litmus paper and note that the litmus gets blue, alkaline. 

193 Pour 5 Cc. of MgS0 4 solution in each of two test-tubes: to one* add 
KHO and to the other NH.HO. Note that NH 4 HO precipitates only half as 
much Mg(HO).,, the rest being held in solution by the ammonium salt. Add 
to the smaller precipitate strong NH 4 C1 solution and it dissolves. 



104 ESSENTIALS OF CHEMISTRY. 

precipitated whenever a soluble phosphate in neutral or alkaline 
solution finds itself in the presence of an ammonium salt, as occurs 
in the alkaline fermentation of urine. 194 

Physiological. Magnesium oxide and hydrate being alkaline 
and tasteless, are popular antidotes for acids. These and the 
carbonate are given to correct acid conditions of the digestive 
tract, and combining with the acids they form soluble salts that 
are laxative. 

ZINC. — When heated in air, zinc burns with an intense bluish- 
white light, forming clouds of oxide. 195 It tarnishes quickly in air 
or water, but becomes coated with a film of oxide that protects 
it from further corrosion. Iron coated with zinc (" galvanized 
iron") will withstand exposure to the weather an indefinite time. 
Alloyed with copper, zinc forms brass. Pure H 2 S0 4 is unaffected 
by pure zinc or zinc coated with mercury (amalgamated), unless 
it forms a galvanic circuit. 196 Commercial zinc is rapidly attacked 
by most acids. 

Zinc Sulphate — ZnS0 4 — White Vitriol — is made thus : — 

Zn + H 2 S0 4 = ZnS0 4 + H 2 . 

White, soluble salt, resembling MgS0 4 in appearance ; astringent 
and emetic. 

Zinc Chloride — Zx£\ 2 —Made :™ Zn + 2HCl-ZnCl 2 f H 2 . 
A white deliquescent salt, strongly astringent ; severe caustic. 
Used as an injection or a bath to preserve anatomical subjects. 



194 A mmonio- Magnesium Phosphate. To a MgS0 4 solution add NH 4 C1 to 
prevent the precipitation of Mg(HO) 2 and then NH 4 HO and finally Na 2 HP0 4 . 
Note the precipitation of ammonio-magnesium phosphate, the so-called 
" triple phosphate " in fern-like crystals. 

195 Zinc. Metal. After noting the color, lustre, weight, hardness, etc., of 
zinc, hold it in the Bunsen flame with forceps and see it volatilize and burn. 

19,i Sulphate. Put bits of zinc in a test-tube and add dilute H 2 S0 4 . Note 
the heat produced and the vigorous evolution of hydrogen, which test by igni- 
tion, etc. Pour in a little mercury and agitate : the action ceases as soon as 
the zinc is amalgamated. Drop in a bit of copper and it begins again. 

197 Chloride. To bits of zinc in a test-tube add HC1 and note the reaction, 
evolution of hydrogen. When action ceases, evaporate a few drops of the 
solution on a watch-crystal and note crystals of ZnCl 2 . 



PART I. — INORGANIC CHEMISTRY. IO5 

Each of the following mixtures forms a hard, white mass, used 
for filling teeth : — 

(a) A strong solution of zinc chloride with zinc oxide. 

(£) A strong solution of magnesium chloride with magnesium 
oxide. 

(e) Zinc oxide with phosphoric acid (zinc oxy phosphate). 

Zinc Carbonate — ZnC0 3 — is a white, insoluble powder made 
by precipitation : — 

ZnSO, + Na 2 C0 3 = Xa 2 S0 4 + ZnC0 3 . 

Used in medicine as a dusting powder for excoriated surfaces, 
and in ointment. 

Zinc Oxide — ZnO — is prepared either by burning metallic zinc 
or heating the carbonate, ZnC0 3 — ZnO + C0 2 . 198 

It is a yellowish-white powder, used externally in ointment \ in- 
ternally as a tonic and astringent, especially in the night-sweats 
of phthisis and diarrhoea of children. 

Zinc carbonate and oxide (pearl white) are often used as white 
pigment having the advantage of lead carbonate in not being 
blackened by sulphur compounds and in not being poisonous. 

Zinc Sulphide — ZnS — is precipitated 1 '" whenever a solution of 
a zinc salt is added to the solution of a soluble sulphide, unless 
the solution is acid in reaction. It is the only white sulphide, 
therefore a test for zinc. 

Poisoning. — All the salts of zinc that are soluble in the digestive 
fluids act as irritant poisons. Sodium chloride and organic acids 
dissolve metallic zinc ; therefore food kept in galvanized iron ves- 
sels is more or less poisonous, especially since commercial zinc 
usually contains traces of arsenic. For this reason articles in- 



198 Oxide. Heat white-hot a lump of ZnC0 3 and note the resulting ZnO, 
and that it dissolves with acid without effervescence. 

19? Precipitates. Test successive portions of a solution of a zinc salt : (a) 
add Na 2 C() 3 = white ZnC0 3 ; [b) add KHO = white Zn(2HO).,, redissolved 
in excess of KHO but not reprecipitated by boiling or by NH + C1; (c) add 
NH 4 HS = white ZnS soluble in excess and in acids except acetic; (a 7 ) add 
K 4 FeCy 6 = white Zn^FeCyg, insoluble in HC1. 
8 



106 ESSENTIALS OF CHEMISTRY. 

tended for toxicological analysis should never be kept in jars with 
zinc caps. 

CADMIUM. — This is a comparatively rare metal; it is found 
in certain zinc ores ; a bluish-white metal softer than zinc ; 2C0 
enters into several important alloys. Its salts resemble those of 
zinc in uses and properties except that some are employed in 
photography, and that its sulphide 201 is a bright yellow, insoluble 
in HC1 and most acid solutions. 202 

Aluminum Group. 

Boron B n 

Aluminum Al 27 

Scandium Sc 44 

Gallium Ga 70 

Yttrium Yt 90 

Iridium In 113 

Lanthanum La 1 39 

Cerium Ce. 141 

Neodymium Nd 141 

Praseodymium Pr 144 

Samarium Sm 150 

Erbium . . E 166 

Ytterbium Yb 173 

Thallium Tl 203 

Group Characteristics. — Trivalent. Boron is so weakly posi- 
tive that it is a non-metal. The others are rare metals, except 
aluminum, the most abundant of metals. So many of their com- 
pounds, especially the oxides, hydrates and silicates, are of a 
neutral, insoluble, infusible, inert and earthy character that the 
group is often called "the metals of the earths." 

BORON occurs in the boric acid of the steam-jets in certain 

200 Cadmium. Metal. After noting the physical properties of a bit of cad- 
mium, heat it under the blow-pipe and note that it burns, but with the forma- 
tion of a brown oxide. 

201 To a solution of CdS0 4 add NH 4 HS and note yellow precipitate of CdS. 
** 02 Sulphide. Add HC1 to the cadmium in a test-tube and pass H 2 S and 

note yellow precipitate of CdS. 



PART I. — INORGANIC CHEMISTRY. IO7 

volcanic regions and in deposits of borax, especially in California 
and Nevada. Boron has two allotropic forms, amorphous and 
crystalline, corresponding to the coal and diamond forms of car- 
bon. Boron colors the flame green. 203 

Boric Acid (B 2 3 + 3H 2 = 2H3BO3 = (ortho) Boric acid) 
was formerly called boracic acid from its relation to borax, the 
sodium salt from which the element itself was named ; pearly 
scales," 04 soluble in water and alcohol, feebly acid, slightly bit- 
terish, almost tasteless, and unirritating. Boric acid alone, or 
combined with glycerine (boroglyceride) is a very efficient and 
non-poisonous antiseptic. 

Borax is official as sodium borate (Na2BiO7.10H.2O) and often 
called sodium biborate, though it is properly a tetraborate. A 
soluble, mildly alkaline salt of some antiseptic power, and so is 
used as a wash for infectious and parasitic inflammations. When 
fused it combines with various oxides, and is therefore used to 
clean off metallic surfaces in soldering, brazing and welding. 

ALUMINUM is never found free, but in the abundance and 
distribution of its compounds (clay and many common rocks) it 
ranks next to oxygen and silicon — third among the elements and 
first among the metals. It is a very light (sp. gr. 2.6) bluish- 
white malleable metal, practically unaffected by air, water and 
many acids, though HC1 and the alkalies attack it energetically/ " 
It is also acted upon by certain vegetable acids, especially in the 
presence of common salt. Its ores, though abundant, unfortu- 
nately do not yield the metal on being simply heated with carbon,- 12 

203 To a crystal of borax add a few drops of H 2 S0 4 and about 5 Cc. of 
alcohol; ignite and note the green color the H 3 B0 3 gives the flame. 

201 Boron. Boric Acid. Heat 5 Cc. of water and about 1 Gm. of borax in 
a test-tube; to this saturated hot solution add HC1 and note the separation 
of white crystals of H 3 B0 3 . 

200 Melt 1 Gm. of H 3 B0 3 in an iron spoon (doll tin-spoons can be bought 
for a few cents a thousand; and it loses its 3ti 2 and becomes a sticky, glassy 
mass of B 2 3 . 

206 Aluminum. Metal. Note the physical properties of a bit of aluminum; 
that it does not dissolve in R 2 S0 4 , HNO a or NH 4 HO, but that in HC1 or 
KHO it dissolves readily with the evolution of hydrogen. 



108 ESSENTIALS OF CHEMISTRY. 

but recently devised electric methods are now, especially at 
Niagara and at Neuhausen on the Rhine, increasing and cheap- 
ening the output. The metal is especially valuable in its alloys, 
giving to other metals increased strength, incorrodibility and 
facility of casting. 

Aluminum Oxide, AI 2 8 , occurs native as corundum, which 
when pulverized is emery ; its finely crystallized forms, the sap- 
phire and ruby, are now also made artificially. 

Aluminum Hydrate, A!( HO) 3 , soluble in acids or excess of 
of alkalies, falls as a gelatinous precipitate whenever an aluminum 
solution is treated with an alkaline hydrate or carbonate.' 20 ' It 
has such affinity for organic matters that it is sometimes used to 
purify water, and is largely employed as a " mordant " to fix 
organic colors in dyeing. 211 

Aluminum Chloride — A1 2 C1 6 — Prepared industrially in the 
manufacture of aluminum. A soluble, astringent salt. It absorbs 
and combines with H 2 S, PH 3 , and NH 3 . An impure solution is 
sold as a disinfectant under the name chloralum. 

Aluminum Sulphate — A1 2 3S0 4 . Made by treating white clay 
with H 2 S0 4 . It has properties similar to the foregoing. 

Alum — A lumen. — An alum is a double sulphate of a trivalent 
and univalent radical, 212 crystallizing in regular octohedra with 12 
molecules of water of crystallization. Its constitution may be 
expressed thus : — 

R 2 m 3S0 4 .R 2 T SO„ or 2R m R (2SO,). 

207 Hydrate. To an aluminum solution (sulphate or chloride) add KHO 
and note gelatinous precipitate of aluminum hydrate, redissolving in excess of 
KHO. Note too that the same precipitate is formed ( 208 ) by NH 4 HO; (* 209 ) 
by Na,C0 3 with evolution of C0 2 ; and ( 210 ) by NH 4 HS with evolution of 
II 2 S. 

211 Mordant. Color an aluminum solution with cochineal and add 
NH 4 HO; note that the precipitated hydrate takes the coloring matter and 
settles in red masses (" lakes ") leaving the solution clear. 

212 Alum. Mix a solution of A1.,(S0 4 ) 8 with one of K.>SO + and evaporate 
until it crystallizes. Lay some of these alum crystals on a piece of charcoal 
and heat mildly with the blowpipe; note that they melt and lose their water 
of crystallization and become an amorphous mass of " burnt alum." Next 
heat as intensely as possible and note that the carbon of the charcoal does 
not reduce the aluminum compound to the metallic state. 



PART I. — INORGANIC CHEMISTRY. IO9 

The trivalent radical (R m ) may be Al, Fe, Cr, or Mn. The 
univalent radical (*) may be K, Na, NH 4 , etc. So by different 
combinations of these radicals a variety of alums may be formed. 
The old potash alum (AL(3S0 4 ) 3 .KoS0 4 ) is giving place in the arts 
to the cheaper am monium alu m (AL(3S0 4 ) 3 .(NH 4 )._S0 4 ). The 
ammonio-ferric alum (Fe. J (3S0 4 ) 3 .(NH 4 )oS0 1 ) is also much used 
in medicine. Burnt alum, alu men exsicca/um, is a white amor- 
phous powder obtained by heating alum until its water of crystal- 
lization is driven off. Alum, like^other salts in which the acidu- 
lous radical predominates, is astringent ; burnt alum, on account 
of its avidity for water, is a mild escharotic. 

Aluminum Silicates, very abundant in granite, feldspar, etc., 
and in the clays resulting from the disintegration of these rocks. 
Clay remaining where formed, is generally quite pure and white 
(kaolin or china-clay), but if deposited by water it is usually 
reddish or brown from admixtures of metallic oxides, especially 
iron. 

Kaolin is used in medicine, from its inertness, as a dusting 
powder and as a vehicle for the application of certain corrosive 
chemicals. Pottery, earthenware and porcelain are made of 
clay mixed with some fusible silicate which, on heating, melts 
and binds the particles of clay together more or less firmly. 

CERIUM is a rare metal. One of its salts, the oxalate, 
Ce 2 (C 2 4 ) 3 , is used as a sedative to irritable stomachs, especially 
in the vomiting of pregnancy. When pure it is a very efficient 
remedy; but the commercial article is liable to contain salts of 
lanthanum, neo- and praseodymium, and other allied metals. 

The other members of this group are of little medical interest. 
The oxides of some of them — the "rare earths" — especially of 
cerium, together with zirconium and thorium, are used to make 
the mantle of the Welsbach burner, which heated in the air-gas 
(Bunsen) flame gives a strong white light. 



IIO ESSENTIALS OF CHEMISTRY. 

X. The Iron Group. 

Chromium, Cr 52 

Manganese, Mn 55 

Iron, Fe 56 

Cobalt, Co 59 

Nickel, Ni . ; 59 

Molybdenum, Mo 96 

Tungsten (Wolfram), W 184 

Uranium, U 240 

These are hard metals and all more or less magnetic. 

By a variation in valence they form two classes of compounds : 
One in which the atom is bivalent, as in ferrous chloride (FeCl 2 ) ; 
the other in which the atom is trivalent, as in ferric chloride 
FeC) 3 . With excess of oxygen they form acidulous radicals, which 
form the chromates, manganates, and ferrates, with the stronger 
bases. 

CHROMIUM. — So named because all its compounds are 
colored. The metal is of but little use. Its compounds are of 
great importance to the chemist and of considerable utility in the 
arts, but few are used in medicine. 

Chromic Oxide, Cr 2 3 , chromium sesquioxide, is a bright green 
powder used in paint as chrome-green. 213 

Chromium Trioxide — Cr0 3 — is made by treating a strong solu- 
tion of potassium bichromate with sulphuric acid, thus : — 

K 2 Cr 2 7 + H 2 S0 4 = K 2 S0 4 + H 2 Cr0 4 + Cr0 3 . 

The Cr0 3 separates in crimson prisms.' 214 It is a powerful oxidant 
and a caustic. Sometimes improperly called chromic acid. 

Chromates. — The principal ones are potassium chromate, 
K 2 Cr0 4 , a valuable test reagent, and lead chromate, PbCr0 4 , a 
yellow pigment. 

2 M Chromium. Sesquioxide. Rub up together about 5 Gm. of K 2 Cr 2 7 
and 1 Gm. starch; ignite this in an iron spoon; remove the K 2 C0 3 by wash- 
ing and then note the green mass of Cr 2 3 . 

m Trioxide. Mix together equal parts of strong H 2 S0 4 and saturated solu- 
tion of K 2 Cr 2 7 . Note as it cools the separation of crimson prisms of Cr0 3 . 



PART I. INORGANIC CHEMISTRY. Ill 

Bichromates are not regular acid- or bi- salts, but compounds of 
a chromate and chromium trioxide. The most important of 
these is potassium bichromate, K 2 Cr 2 7 , or K,Cr0 4 .Cr0 3 . It 
forms large, red, soluble crystals. It is added to the sulphuric 
acid in batteries to oxidize 215 the nascent hydrogen. 

Chromates may be recognized by their color and by the yellow 
precipitate on the addition of lead acetate. 222 

MANGANESE resembles iron in its properties. Used to alloy- 
iron in the preparation of c rtain kinds of steel. Its most abun- 
dant ore is the 

Manganese Dioxide — Mn0 2 — Black Oxide of Manganese — an 
insoluble steel-gray powder that readily gives us its extra atom of 
O. Used in large quantities in the preparation of chlorine and 
oxygen gas.' 224 

Manganous Sulphate — MnS0 4 . 

Mn0 2 — H 2 S0 4 = MnSO, — H 2 - O. 



215 Oxidation. Rinse a beaker with strong alcohol and drop in a crystal ot 
Cr0 3 and note that the thin film of alcohol ignites; (* 2lh ) moisten a pledget of 
cotton with absolute alcohol and lay a crystal of Cr0 3 on it, and it ignites; 
( 2lT ) boil some match-sticks with battery fluid (K 2 Cr ? 7 10 per cent., water 
80 per cent., and H 2 S0 4 10 per cent.), and note that they are consumed with 
evolution of C0 2 . 

218 Chromic Salts (green). To some K 2 Cr.,0 7 solution in a test-tube add 
HC1 and alcohol and boil. Note the odor of aldehyde from oxidation of the 
alcohol and the green color of CrCL. (- Iy ) To some K 2 Cr.,0 7 solution add 
H. 7 S0 4 and alcohol, and boil; note the green color of Cr.,(S0 4 )..; put a few 
drops on a watch-glass and when it dries, note the crystals of chrome alum 
(Cr,3S0 4 K,S0 4 ) or KCr(SOJ 2 . 

2 -'° Chromates. To a solution of K 2 Cr 2 7 add KHO; note that K 2 Cr0 4 is 
formed and the solution becomes yellow. To successive portions of this 
K 2 Cr0 4 add ("') BaCl 2 , and note yellow precipitate of BaCr0 4 ; (- 2i ) 
Pb(C 2 H 3 2 ) 2 and note yellow precipitate of PbCr0 4 , and ( ;2{ y AgX0 3 and 
note deep red of Ag 2 Cr0 4 . 

m MANGANESE. Chloride. Warm some MnO., and HC1 in a beaker, under 
a hood or in the open air to avoid inhaling the C'l evolved, and filter. As the 
filtrate is sure to contain iron, add Na,CO s gradually with constant stirring as 
long as reddish brown Fe^HO) s is thrown down and until the flesh-colored 
MnC0 3 begins to precipitate, then filter and label MnCl 2 . To successive por- 
tions of the MnCl 2 solution (-- 5 ) add XH t HS and note a pale pink precipitate 
of MnS, the only flesh-colored sulphide known, and hence characteristic; 
( 226 ) add NH 4 HO and note flesh-colored precipitate of Mn(HO) 2 soluble in 
excess of NH 4 HO. 



I I 2 ESSENTIALS OF CHEMISTRY. 

A soluble, rose-colored salt, employed in medicine and also in 
dyeing. 

Manganous Sulphide — MnS — is precipitated whenever a solu- 
tion of a salt of manganese is treated with NH 4 HS. It is the only 
flesh- colored sulphide ; hence its formation is a testoi manganese. 225 

Manganates. — If a mixture of KHO, KC10 3 , and Mn0 2 is 
heated together, there results a green mass of potassium mangan- 
ate, K 2 Mn0 4 . If this is dissolved in distilled water, it forms a 
green solution, which, on boiling, or even standing awhile, is 
changed to a purple, owing to the formation of potassium perman- 
ganate, K 2 Mn 2 8 . 227 

The permanganate 2 ' 29 gives up its oxygen so readily to organic 
matter, at the same time losing its purple color, that it is used as 
a test for organic impurity in water and as a disinfectant. 

Physiological. — Associated with iron (i to 20), manganese is a 
normal constituent of the blood corpuscles ; hence its prepara- 
tions, like those of iron, are blood tonics. Valuable in amenor- 
rhcea. 

IRON occurs abundantly in oxide, carbonate, and sulphide ; 
occasionally free, as in meteorites. 

Preparation. — The oxides and occasionally the carbonates are 
the ones used for the preparation of iron. The oxide is heated 
in a blast furnace with coal and fluxes (limestone and silicates). 
The carbon of the coke removes the oxygen from the iron, which 
melts and sinks beneath the melted fluxes. The fused metal is 

227 Borax-bead. Melt in the flame a lump of borax on the looped end of 
a platinum wire until it loses its water of crystallization and fuses into a clear 
glass bead; touch this to the manganese solution and again fuse it. Note 
that the bead is colored violet or amethystine. 

228 Manganates. Into a porcelain crucible put equal parts of Mn0 2 , KHO 
and KC10 8 and heat strongly. When quite cool add water and dissolve out 
the K 2 Mn0 4 , which is a beautiful green. Pour some of this into a beaker of 
water and note that it changes to violet, K 2 Mn 2 8 with a precipitate of man- 
ganic hydrate. 

229 Oxidation. To some powdered K 2 Mn 2 8 in a dish add a few drops of 
H^SOj. and note the odor of ozone. ( 2:{0 J Add a few drops of strong alcohol 
and it ignites. 



PART I. INORGANIC CHEMISTRY. 



"3 



then drawn off into sand or iron molds. This is pig, or cast iron, 
containing 4 to 5 per cent, of carbon. Wrought iron contains 
little or no carbon ai and steel an intermediate quantity. 

Properties. — A bluish-gray metal, sp. gr. 7.5 * rusts (oxidizes) 
when exposed to moist air or water containing air. 

Reduced Iron. — Ferrum Redactum, iron by hydrogen, Que- 

Fig. 42. 




Making Reduced Iron. 

venne's iron. — It is prepared by heating ferric oxide nearly to 
redness in a tube through which hydrogen is passed : &i 
FeA+H 6 = Fe 2 + 3 H 2 0. 
It is a very fine, dark gray powder, which, if good and fresh, 
will ignite' 283 on contact with a lighted taper and burn with a red 
glow ; prescribed in pill form. 

231 Iron. Metal. Pour 10 Cc. of dilute H 2 S0 4 into each of two test-tubes. 
Into one drop a small fragment of cast iron'; into the other some wrought 
iron, as tacks; set aside, and when all is dissolved note that the cast iron 
leaves a residue of graphite carbon and the wrought iron leaves no residue. 

-^ Reduced Iron. In the apparatus shown in Fig. 42 (rather tedious and 
troublesome for a class exercise) hydrogen is generated from sulphuric acid 
and zinc in the Wolff bottle, and dried by passing through the U-shaped tube 
containing calcium chloride. It then passes through the porcelain tube con- 
taining ferric oxide (subcarbonate, U. S. P.) which is heated to redness in the 
furnace. After the reduction is completed, the iron should not be exposed to 
the air until cool, or it will ignite spontaneously. 

Let the student ( 233 ) (Faraday's experiment) pour a mixture of reduced 



114 ESSENTIALS OF CHEMISTRY. 

CHLORIDES. 

Ferrous Chlortde — FeCl 2 . — Made by adding iron to hydro- 
chloric acid until effervescence ceases, thus : — 

Fe + 2HC1 = FeCl 2 -f H 2 

Like most ferrous salts, it is green and prone to oxidize with the 
formation of the ferric compounds. 

Ferric Chloride — FeCl 3 — is made by first forming the ferrous 
chloride as above, and then adding nitric and hydrochloric acids. 
The nascent chlorine evolved by the nitro-hydrochloric acid con- 
verts the ferrous into ferric chloride, thus : — 

6FeCl 2 -f 6HC1 + 2IINO, = 6FeCl 3 +N 2 2 + 4H 2 0. 

The liq.ferri chlorirfi, U. S. P., is the aqueous solution. This, 
when diluted with alcohol, forms the tinct. ferri chloridi, U. S. P. 
If citrate of potassium or sodium is added to this tincture, the 
solution loses its styptic taste, does not affect the teeth, and is not 
incompatible with solutions containing tannin. 

sulphates. 

Ferrous Sulphate — FeS0 4 — Copperas, Green Vitriol. — Pre- 
pay erf: Fe + H 2 SO, = FeSO, + H 2 . 235 - Soluble, green crystals 
efflorescing upon exposure. A cheap and excellent disinfectant, 
destroying organic matters by abstracting their oxygen. When 
given in pill form it is first exsiccated. 

Furric Sulphate — Fe 2 (S0 4 ) 3 . — Tersiclphate is made by adding 

iron and gunpowder into alcohol burning m a dinner-plate and note that the 
iron burns with bright scintillations, while the gunpowder falls through the 
flame and is not ignited uniil the alcohol is burned away to the surface of the 
plate. ("***) Make an iron gunpowder by mixing I Gm. of reduced iron, 2 Grn. 
of sulphur and 3 Gm. of KN0 3 , and note that it burns as quickly and more 
brilliantly than ordinary gunpowder. 

2 5 Ferrous Salts. Dissolve iron filings in warm dilute H 2 SO,. Allow a 
drop of the solution to evaporate on a watch-crystal and note greenish crystals 
of FeS0 4 . 



PART I. INORGANIC CHEMISTRY. 115 

nitrosulphuric acid (HN0 3 + H 2 S0 4 ) to a solution of the ferrous 
sulphate, 241 thus : — 

6FeS0 4 -f- 3H.SO, + 2HNO3 = Fe 2 (S0 4 ) 3 -f N 2 2 + 4 H 2 0. 
Its officinal solution is the liq. ferri tcrsiilphatis. Liq.ferri sub- 
sulphatis, U. S. P., Monsel's Solution, is prepared similarily to 
the above, except using only half the quantity of sulphuric acid. 

Fig. 43. 




A Dialyzer. 

Ferrous Hydrate — Fe(HO) 2 — is precipitated on mixing solu- 
tions of a hydrate and a ferrous salt, 236 as — 

FeSO, — 2NaHO = Na,SO t 4- Fe(HO) 2 . 
A green precipitate, which soon oxidizes and becomes brown. 
Ferric Hydrate — Fe(HO) 3 . — A brownish red, gelatinous mass, 
precipitated by soluble hydrates from ferric solutions, 24 ' 2 e. g. : — 
FeCl, -f 3NH 4 HO = 3NH 4 C1 + Fe(HO) 3 . 
This is the favorite antidote for arsenic, for which purpose it 
must be freshly prepared and given in large doses. Ferric hydrate 

Ferrous Precipitates. To successive portions of fresh FeS0 4 solution add : 

2: ' ,6 KHO = greenish-white precipitate of Fe(HO) 2 . 

2: ' 7 Na 2 C0 3 = greenish-white precipitate of FeC0 3 . 

2: ^Nti + HS = black precipitate of FeS. 

2 ' 9 K 4 (FeCy 6 ) = pale-blue precipitate of FeK 2 (FeCy 6 ). 

2;0 K 3 FeCy 6 = deep-blue precipitate of Fe 3 (FeCy 6 ) 2 . 

241 Ferric Salts. To a solution of FeSO + add a few drops each of H 2 S0 4 
and HX0 3 . It turns dark-brown, but on heating changes to a light-red solu- 
tion of Fe 2 (S0 4 ) 3 . 

Ferric Precipitates. To successive portions of a ferric solution add : 

242 KHO = reddish-brown precipitate of Fe(HO) 3 . 



Il6 ESSENTIALS OF CHEMISTRY. 

dissolves freely in a solution of ferric chloride, forming a dark red 
liquid of a styptic taste. 

If this liquid is put in a dialyzer (Fig. 43), a vessel with a bot- 
tom of parchment or animal membrane, and suspended in water, 
the chloride passes out through the membrane into the water. 
When barely enough ferric chloride remains within the dialyzer to 
hold the ferric hydrate in solution and the styptic taste has dis- 
appeared, the liquid is removed and sold under the name of 
" Dialyzed Iron." 

Ferric Nitrate — Fe(N0 3 ) 3 . 

Made: Fe(HO) 3 4- 3 HN0 3 - 3H./) + Fe 3 N0 3 . 

Liq. ferri nitratis, U. S. P., is a reddish acid liquid. Used as 
an astringent, especially in dysentery. 

Ferrous Iodide — FeL. — Prepared: Fe + I 2 = Fel 2 . 

Sometimes given in pill, but better with syrup, which acts as a 
preservative as well as a vehicle. 

Ferpous Carbonate — FeC0 3 — is obtained by adding a soluble 
(alkaline) carbonate to a ferrous salt,' 287 thus : — 

FeS0 4 + K 2 C0 3 = K 2 S0 4 + FeC0 3 . 

It is insoluble in pure water, but slightly soluble in water con- 
taining carbonic acid, as in chalybeate springs. On exposure to 
the air it turns red from formation of ferric hydrate ; so it is pre- 
served by mixing with sugar and honey, as in the ferri carbonas 
saccharaius, U. S. P. 

Ferrous Sulphide — FeS 238 - — does not occur native, but is made 
by heating together iron filings and flowers of sulphur. Used in 
the preparation of H 2 S. Iron pyrites (FeS 2 ) is a common ore 
largely used in the manufacture of sulphuric acid and copperas. 

Scale Compounds of Iron. — These are ferric salts, mostly with 



2,3 Na 2 C0 3 = reddish-brown precipitate of Fe(HO) 3 . 
2,4 NH 4 HS = black precipitate of FeS. 
245 K 4 (FeCy 6 ) = deep-blue precipitate of Fe 4 (FeCy 6 ) 3 
216 K 3 FeCy 6 = greenish-brown color. 
247 K(CyS) = deep-red color, discharged by HgCl 2 . 



PART I. INORGANIC CHEMISTRY. 117 

organic acids. They do not crystallize readily, but are sold as 
thin scales. Made by evaporating their solutions to a syrupy 
consistence, poured upon plates, and when dry peeled off in 
scales. Often other bases, as potassium or ammonium, together 
with alkaloids, as quinine and strychnine, are incorporated into the 
compound. 

The following are officinal : Ferri citras, ferri et ammonii 
citras, ferri et quinice citras, ferri et strychnice citras, ferri et am- 
monii tar iras, ferri et potassii tartras, and ferri pyrophosphas. 

Physiological. — Iron is a normal constituent of the body, espec- 
ially of the blood corpuscles, where it performs an important func- 
tion, as is shown by the great increase of blood corpuscles and of 
bodily vigor attending its administration. Many of its salts, 
especially the ferric salts of the mineral acids, are astringent and 
hemostatic. Iron is eliminated by various organs, but is mainly 
discharged by the bowels as sulphide, blackening the faeces. 

COBALT. — Its chief ore is a compound with arsenic, sold 
under the name of cobalt ox fly stone, for poisoning flies. Its salts 
are used in preparing sympathetic ink,' 248 for when dried and de- 
prived of water of crystallization, they are a deep blue, but become 
almost colorless (slightly pinkish) on regaining it. Writing done 
with a dilute solution of chloride of cobalt is invisible until 
warmed, when it becomes blue, the color disappearing when the 
paper is cooled or moistened, especially in a damp air. 

NICKEL. — This is a hard, grayish-white metal that does not 
tarnish in the air. 250 Used to electro-plate instruments made of 
metals more prone to corrode, and to make cheap coin. Mixed 
with brass, it forms German silver. 

248 Cobalt. Sympathetic ink. Dip a clean pen into a cobalt solution and 
write on paper (better of pinkish tint). Note that the writing is invisible but 
becomes deep-blue on carefully drying (avoid scorching) over a lamp, and that 
it disappears again on cooling by blowing the damp breath on it. 

249 Touch a borax bead to a cobalt solution and heat; note the deep-blue 
color. 

250 Nickel. Note the physical properties of the metal and that neither 
H 2 S0 4 nor HCl affect it much, though HN0 3 attacks it vigorously. 



Il8 ESSENTIALS OF CHEMISTRY. 

MOLYBDENUM, TUNGSTEN, and URANIUM are rare 
metals and of little importance except that some of their com- 
pounds have found a limited application in chemistry and the arts. 
Ammonium molybdate is a valuable test for phosphoric acid and 
the alkaloids, and phospho-molybdic acid is a reagent for alka- 
loids. Sodium tungstate, Na 2 W0 4 , has long been used to render 
fabrics uninflammable, and recently has attained considerable 
popularity as a test for albumin in urine. Uranium salts are used 
to color glass and impart to it a remarkable fluorescence. 

Copper Group 

Copper ( Cuprum) Cu 63.4 

Mercury ( Hydrargyrum) 13 g 2co 

Silver (Argentum) Ag 108 

Gold {Auruni) Au 197 

Group Characteristics. — Copper and mercury are both univa- 
lent and bivalent, forming two classes of compounds, "ous" and 
" u" Silver being only univalent and gold both univalent and 
trivalent, they do not strictly belong to this group, yet their 
chemical behavior is much like that of copper and of mercury. 
They are all very weakly positive and indifferent to the negative 
radicals, and hence quite permanent in air and water, and at or- 
dinary temperatures but slowly acted upon by most chemicals. 

COPPER 255 is usually found combined with sulphur, etc., but 
often in the metallic state, especially on the southern shores of 
Lake Superior. Being found free, it was among the first metals 



Precipitates. To successive portions of a nickel nitrate solution add: 

201 KHO = pale-green precipitate, soluble deep-blue by NH 4 salts. 

252 NH 4 HO = pale-green precipitate, soluble deep-blue by NH 4 HO. 

253 NH 4 HS = black precipitate, slightly soluble in excess of NH 4 HS. 

254 Borax bead is colored violet while hot and yellowish-brown when cold. 

055 Copper. Metal. Note the physical properties of a bit of copper and 
that it is attacked very slowly by H 2 S() 4 or HC1, but very vigorously by HN0 3 , 
part of which decomposes to oxidize the metal with the evolution of the lower 
nitrogen oxides and the rest attacks the oxide thus formed. 



PART I. — INORGANIC CHEMISTRY. 1 19 

wrought by man, 256 so the bronze preceded the iron age. Cop- 
per is a red malleable metal ; an excellent conductor of elec- 
tricity. It colors the flame green. 257 . 

Cupric Sulphate — CuS0 4 — Blue Vitriol, Blue Stone, — Obtained 
as an incidental product from silver refineries, copper mines, etc. ; 
made experimentally by heating copper with strong H 2 S0 4 . Forms 
beautiful blue crystals, soluble in water, but insoluble in alcohol. 
If the crystals are heated they lose their water of crystallization 
and form a white powder, which becomes blue again upon the 
addition of water. Hence, used as a test for water in alcohol. 258 
Like other salts in which the acidulous radical predominates, 
cupric sulphate is astringent and coagulates albumen. A prompt 
emetic, but not used as much as ZnS0 4 , because if, by chance, it 
be not all ejected from the stomach, a gastro-enteritis is liable to 
be set up. 

Cupric Hydrate. — Cu(HO) 2 — is formed as a bluish- white pre- 
cipitate whenever a soluble copper salt is treated with a soluble 
hydrate, 259 thus : 

CuS0 4 + 2KHO = K 2 S0 4 + Cu(HO) 2 . 

When heated, even under water, it decomposes — 
Cu(HO) 2 ==CuO + H 2 0. 

Cupric Oxtde — CuO — Black Oxide. — Prepared by heating 
copper turnings in air. It gives up its oxygen easily, hence used 
as an oxidizer in organic analysis. 

v56 Reduction. Heat 1 Gm. of verdigris mixed with Na 2 C0 3 on a piece of 
charcoal in the reducing blowpipe flame and note the globules of metallic 
copper set free. 

' 2o1 Flame. Dip a platinum wire into a copper solution and note that it 
colors the flame green. 

258 Sulphate. After noting appearance, taste, etc., of a crystal of CuS0 4 , put 
it into a test-tube and heat carefully; note that the salt gets amorphous 
white, losing its water of crystallization. When cool add strong alcohol and 
shake; note that there is little change. Add to the alcohol a few drops of 
water and shake, and note the presence of water is shown by the CuS0 4 tak- 
ing again water of crystallization and becoming blue. 

259 Oxides. To a solution of CuS0 4 add KHO and note a blue precipitate 
of Cu(HO) 2 insoluble in excess of KHO. Boil and note that the Cu(OH) 2 de- 
composes into black cupric oxide and water (Cu(HO) 2 = CuO +H 2 0). 



120 ESSENTIALS OF CHEMISTRY. 

Cuprous Oxide — Cu 2 — Suboxide. — Made by boiling the 
cupric oxide' 260 with an oxidizable substance, as glucose (copper 
tests for glucose), which is^oxidized at the expense of the oxygen 
of the cupric oxide. The precipitate is first yellow (hydrate), 
but soon becomes a bright red (oxide). 

Cupric Subacetate or Oxyacetate — sometimes called ver- 
digris (green-gray) — is made industrially by exposing plates of 
copper to the acetic fumes of grape husks, etc. It is likely to be 
formed whenever fruits containing acetic acid are placed in cop- 
per vessels. 

Physiological. — Canned fruits, pickles, etc., that have been 
colored green with copper, and food, especially if acid, that has 
been cooked or kept in copper vessels, are liable to produce an 
acute gastro enteritis. Chronic copper poisoning, so called, is 
perhaps always due to other substances, as lead or arsenic, and 
should be treated accordingly. 

Antidotes for acute copper poisoning : Encourage vomiting and 
give albumen (white of egg), which combines with the copper 
salt to form an insoluble albuminate ; or iron filings, which will 
precipitate the copper in metallic state.' 262 

( 26 °) Next add some glucose solution and boil; note that the glucose takes 
part of the oxygen from the black CuO and reduces it to red Cu 2 G. 

261 Hydrates. Precipitate Cu(HO) 2 as in preceding exercise. Then add 
glucose solution and note that it dissolves the Cu(HO) 2 , forming a deep-blue 
solution. Boil, and note that the glucose deoxidizes the Cu(HO) 2 and pre- 
cipitates the yellow Cu 2 (HO) 2 , which rapidly decomposes (Cu 2 (HO) 2 = 
Cu 2 -f- H 2 0) into water and red cuprous oxide — the mixture having changed 
from a deep blue solution through green to a yellow precipitate, which in turn 
changes from yellow through orange to red. This is the alkali-copper test for 
glucose, as well as the alkali-glucose test for copper; for when substances re- 
act characteristically, each is a test for the other. 

Other Tests. Test successive portions of a copper solution as follows : 

262 Dip in a needle or other bright bit of iron, and note it is plated with 
copper. 

•263 p ass \\^ or add NH 4 HS and note black precipitate of CuS. 

264 Add NH 4 HO and note deep-blue solution of Cu(NH a ) 2 S0 4 . 

265 To the above ammonio-cupric solution, if not too alkaline, add arsenic 
water and note bright green precipitate of Paris- green (CuHAs0 3 ). 

266 Add K 4 (FeCy 6 ) and a drop of acetic acid and note brownish-red cupric 
ferrocyanide (Cu 2 FeCy 6 ). 



PART I. INORGANIC CHEMISTRY. 121 

MERCURY is the only metal liquid at ordinary temperatures, 
and resembles silver in appearance ; hence the names hydrargyrum 
(water silver) and quicksilver (fluid silver). It is so heavy (spe- 
cific gravity 13.56) that iron and stone float upon it as corks on 

Fig. 44. 



water. (Fig. 44 represents a marble and a ball of iron floating 
on mercury.) It does not tarnish in the air unless contaminated 
with baser metals ; dissolves most metals/ 67 except iron, to form 
" amalgams." m 

Uses. — Metallic mercury is used extensively in the refining of 
silver and gold, in thermometers and other instruments, with tin 
in silvering mirrors, and in many other branches of the arts. 
Metallic mercury, rubbed up with various excipients until globules 
cease to be visible, 269 forms several officinal preparations. Rubbed 
with chalk, it forms "gray powder," hydrargyrum cum creta; with 
honey of rose and licorice powder, it forms " blue pill," massa 
hydrargyri; and with lard and suet it forms "mercurial ointment," 
unguentum hydrargyri. The therapeutic activity of these prepara- 
tions is due not to the metallic mercury they contain, but to small 
quantities of mercurous oxide formed by the oxidation of the 
finely-divided metal. So their strength varies with the thorough- 

MERCURY. Metal. 

267 After noting the physical properties of a small vial of mercury, drop a 
globule into a dish and add a small shot; note that the mercury and lead 
combine, forming an amalgam. 

268 Drop a globule of mercury into AgNCX solution and watch the growth 
of the "arbor Diana" a tree-like formation of silver amalgam. 

269 Rub up a few drops of mercury in a mortar with a little lard and note 
how easily the mercury becomes emulsified, the globules soon becoming so 
small as to be invisible to the naked eye. 



122 ESSENTIALS OF CHEMISTRY. 

ness of the rubbing, the extent of the exposure, and the age of the 
preparation. 

Mercurous Iodide. Hgl. Proto- iodide, yellow iodide 
of mercury, Hydrargyri iodidum flavum U. S. P., is made by 
precipitation ' m from mercurous nitrate and potassium iodide 
(Hg(N0 3 )4-KI-KN0 3 +HgI). It was formerly made by 
rubbing together chemical equivalents, 200 of mercury and 127 
of iodine. Some of the blue globules of mercury remaining un 
combined gave the yellow Hgl a greenish color ; hence it was 
called green-iodide {hydrargyri iodidui7i viride, U. S. P., 1880). 

Mercuric Iodide. Hgl 2 . Red iodide, Hydrargyri iodidum 
rubrutfty U. S. P., is made by precipitation 270 from mercuric 
chloride and potassium iodide (HgCl 2 + 2KI — 2KCI + Hgl 2 ). 
This too was formerly made by rubbing together equivalents of 
mercury (200) and iodine (254). 

The mercuric iodide is dissolved by excess of either the HgCl 2 
or the KI. In precipitating, mercuric iodide is first yellow, but 
rapidly becomes red. If some of the dry red powder is placed 
on a sheet of paper and warmed over a lamp, it changes back to 
yellow, but on shaking or rubbing, the red is restored. These 
changes in color are due to changes in crystalline structure. 

Mercurous Nitrate — HgN0 8 — is formed when mercury is 
treated with cold dilute nitric acid. 

Mercuric Nitrate— Hg(N0 3 ) 2 . — Acid nitrate of mercury is 
formed if the mercury be boiled with strong nitric acid. Like all 

270 To a drop of mercury in a test-tube add HC1 and note that it is un- 
affected; wash out the acid and add HN0 3 and note it gradually dissolved, 
especially if warmed. 

271 Mix a dry salt of mercury with twice the amount of Na 2 C0 3 and heat in 
a dry test-tube. Note that the mercury is reduced and sublimes, forming in 
the cooler part of the tube a deposit of minute globules of metallic mercury. 

272 (Rensch's test.) Boil a strip of bright copper foil in a solution of a salt 
of mercury; or ( ilA ) (galvanic test) drop a few drops of the solution on the 
copper foil and with a bit of zinc or iron (a more positive metal) touch the 
copper through the fluid. Note in either case a plating of metallic mercury 
on the copper and that the mercury may be distilled off by heating the amal- 
gamated copper in a dry test-tube. 



PART I. — INORGANIC CHEMISTRY. 1 23 

other nitrates, both of the above are soluble. It enters into the 
liq. hydrargyri 7iitratis, U. S. P., and " citrine ointment," ung. 
hydrargyri ?iitratis, U. S. P. 

Mercurous Sulphate — Hg._S0 4 — is made by digesting sulphuric 
acid with excess of mercury. 

Mercuric Sulphate — HgSO, — is made by heating mercury 
with excess of sulphuric acid. A white, crystalline salt, used in 
some forms of galvanic batteries. When diluted with water it 
decomposes into an acid salt, which remains in solution, and a 
yellow precipitate of oxysulphate, HgSO^HgO, called "turpeth 
mineral," hydrargyri subsulphas fiavus, U. S. P. 

Mercurous Chloride — HgCl — Calomel, mild chloride, Hy- 
drargyri <Chloridum Mite, U. S. P. — is made by heating mercur- 
ous sulphate with sodium chloride (Hg : S0 4 -f 2NaCl = Na. 2 S0 4 + 
2HgCl), when the mercurous chloride sublimes and is condensed 
in a cool receiver. 

Calomel is a white, insoluble powder.- 75 Exposed to light it is 
slowly decomposed (2HgCl — Hg -- HgCl 2 ). With aqua regia, 
and more slowly with other soluble chlorides, it is converted into 
mercuric chloride. Calomel probably passes through the stom- 
ach unaltered, but is converted into the mercurous oxide by the 
alkaline fluids in the small intestine and slowly absorbed. 

Mercuric Chloride — HgCL — Bichloride of Mercury, Corrosive 
Sublimate — is prepared by sublimation from a mixture of mercuric 
sulphate and sodium chloride, thus : — 

HgSO, 4- 2NaCl ±= Xa,SO, + HgCl 2 . 

It is crystalline and soluble, with a disagreeable styptic taste, 
and is very poisonous ; much used in antiseptic surgery. 

Mercuric Ammonium Chloride — Ammoniated Mercury, White 
Precipitate, U. S. P. — Formed by adding animonia to a solution 



Mercurous Compounds. Treat successive portions of a solution of a mer- 
curous salt HgXO s as follows : 

274 Add KI and note the yellow precipitate of Hgl. 

175 Add dilute HC1 and note the white precipitate of HgCl; filter and heat 
some of the precipitate in a dry test-tube and note it sublimes. 



124 ESSENTIALS OF CHEMISTRY. 

of mercuric chloride • 282 mostly used in ointment. It is a double 
salt of mercury and NH 2 , a derivative of ammonium. Its com- 
position is that of NH 4 C1, in which two atoms of H are displaced 
by one of Hg, forming NH 2 HgCl. The ammonio-sulphate of 
copper, previously described has an analogous composition. 

Mercurous Oxide — Hg 2 — Black Oxide of Me r airy — is made 
by treating a mercurous salt with a soluble hydrate, 276 as — 
2HgCl + 2KHO = Hg 2 + 2KCI + H 2 0. 

It is seldom used in medicine, except in "black-wash" (Jotio 
nigra) made by adding calomel to lime water, and much em- 
ployed in eczema, chancroids and other parasitic affections. 

Mercuric Oxide — HgO — Red or Yellow Oxide. — When pre- 
pared by decomposing mercuric nitrate by heat, it is crystalline 
and of a red color {hydrargyri oxidum rubrum, U. S. P.) ; but 
when made by precipitating a mercuric solution with a hydrate," 81 

HgCl 2 + 2KHO = HgO + 2KCI + H 2 0, 
it is an amorphous yellow powder {hydrargyri oxidum flavum, U. 
S. P.). The yellow variety, being amorphous and more finely 
divided, is less gritty and has greater therapeutic activity. 

Oleate of Mercury is made by warming the yellow oxide with 
oleic acid. A liquid or semi-solid. It is rapidly absorbed when 
applied to the skin. 

Mercurous Sulphide — Hg 2 S — is an unstable compound, which 
falls as a black precipitate when a mercurous solution is treated 
with a soluble sulphide. 278 

Mercuric Sulphide — HgS — falls as a black precipitate when a 
mercuric solution is treated with a soluble sulphide. 283 It is found 
in nature in crystalline masses called cinnabar. By certain pro- 
cesses it may be obtained as a deep-red crystalline powder, called 
vermilion. 

Tests. — These consist in adding, to the suspected liquid, solu- 

276 Add KHO and note black precipitate of Hg 2 0. 

277 Add NH 4 HO and note black precipitate of mercurous ammonium chlor- 
ide (NH 2 Hg 2 )Cl. 

278 Pass H 2 S and note black precipitate of Hg 2 S. 



PART I. — INORGANIC CHEMISTRY. 1 25 

tions of salts containing radicals capable of uniting with mercury 
and of forming precipitates of the foregoing insoluble compounds. 
But the galvanic tesf m is perhaps the best for clinical purposes. 
On a gold or copper coin put a drop of the suspected solution 
acidulated with HC1, and touch the coin through the drop of 
fluid with a piece of baser metal, as a knife blade. Mercury, if 
present, will be deposited on the coin in a silvery film. 

Physiological. — Acute poisoning occurs from swallowing a single 
large dose of some of the mercuric compounds, especially cor- 
rosive sublimate. The minimum fatal dose of corrosive sublimate 
is three grains ; of white precipitate and turpeth mineral forty 
grains. Children tolerate mercury much better in proportion to 
their age than adults. The symptoms are those of severe gastro- 
enteric irritation. Give albumin, with which it forms an insoluble 
compound. Iron filings also act as a chemical antidote by 
decomposing the salt, taking the acidulous radical and depositing 
the mercury in the metallic state. 

Chronic poisoning is often called, from its most prominent 
symptom, salivation or ptyalism. It usually occurs from small, 
but often repeated doses of the mercurous preparations, as blue 
pill, calomel, etc. One of the first symptoms is a delicate red line 
along the margin of the gums ; then comes a metallic taste, ab- 
dominal pains, nausea, vomiting, dysenteric diarrhoea, profuse 
flow of saliva, fetid breath, fever, emaciation, and paralysis. 

Mercuric Compowids. To successive portions (5 Cc.) of a solution of mer- 
curic chloride add : 

279 KI and note precipitate, first yellow and then red, of Hgl 2 . ( 28 °) Dissolve 
this with excess of Kl and make strongly alkaline with KHO, forming the 
solution of potassium-mercuric iodide, called Nessler's reagent. Add a drop 
of this reagent to the most dilute solution of an ammonium salt and note the 
brown precipitate of dimercuric-ammonium iodide (NHg. 2 )I. 

281 KHO and note the yellow precipitate of HgO. 

282 NH + HO and note the white precipitate of mercuric-ammonium chloride, 
(NH 8 Hg)Cl. 

283 H 2 S and note black precipitate of HgS. 

284 Albumen (white of egg) and note white precipitate of mercuric albu- 
minate. 



126 ESSENTIALS OF CHEMISTRY. 

Sphacelation of the mouth and lips sometimes occurs. The 
treatment is to stop the ingestion of poison, and give some 
astringent, as tannin. 

SILVER occurs free, but often as a sulphide associated with 
lead in galena. A white, malleable, ductile metal, capable of a 
high polish ; best known conductor of electricity ; dissolved readily 
by nitric,' 285 but not by hydrochloric or sulphuric acid, except by 
the aid of heat ; does not tarnish in air unless ozone or H 2 S be 
present. 2 "' 

Used to plate mirrors arid articles made of the more corrodible 
metals : alloyed with copper as coin ; for tubes, sutures, etc., in 
surgery, for it does not corrode and irritate the tissues. 

Silver Nitrate — AgNO a — Argenti Mtras, U. S. P., Luna? 
Caustic. Made by the action of nitric acid on silver. If coin 
silver is used, the solution is blue, from the presence of copper. 
Silver nitrate is a crystalline salt, very soluble. Its taste is acrid, 
and in large doses it acts as corrosive poison, destroying the tis- 
sues by coagulating their albumin. For use as a cautery it is 
fused and moulded into sticks. 

Silver Oxide— Ag 2 — is precipitated as a brown powder on 
treating a solution of silver nitrate with caustic potash 290 or soda 

285 Silver. Metal. After noting the physical properties of the silver in a 
dime, dissolve it in HNO a with gentle heat, avoiding the inhalation of the 
fumes. Add HC1 until all the silver is precipitated as AgCl, and filter. Show 
that the copper is retained in the (blue) filtrate by a few of the tests already 
given for that element. Wash the precipitate (AgCl) and add to it, in a 
dish, a little dilute H 2 S0 4 and a bit of zinc : allow it to stand until the next 
day or -next exercise, when the silver will be observed to have separated out 
into a dark spongy mass, and may be fused into a bright button. 

' m Heat with the blow- pipe a little AgN0 3 or charcoal and note that it is 
reduced to a metallic button. 

a8 .' Provide two bits of white cloth blackened with indelible (silver) ink and 
boil one with dilute HNO H and the other with KCy and note that in each case 
the precipitated silver is dissolved out and the black stain removed. 

Insoluble Compounds. To successive portions of AgN0 3 solution add : 

288 KCy and note white precipitate of AgCy soluble in excess of KCy,, 

289 K 2 Cr0 4 and note red precipitate of Ag 2 Cr0 4 . 

290 H 2 S or NH 2 HS and note black precipitate of Ag 2 S. 

291 KHO and note brown precipitate of Ag 2 0. 



PART I. — INORGANIC CHEMISTRY. I 27 

(2AgNO a - 2KHO = 2KNO3 + Ag 2 - R.O). Slightly soluble 
in water. The other salts of silver are insoluble, and made by 
precipitating a solution of silver nitrate with a solution contain- 
ing the appropriate radical. 

Silver Cyanide. — AgCN, may be made by mixing solutions of 
silver nitrate 288 and potassium cyanide (AgN0 3 — KCN = AgCN — 
KNO3). A white precipitate soluble in ammonium hydrate and 
sodium hyposulphite, and in excess of potassium cyanide as in 
the silver-plating bath. It is unaffected by light. 

Silver Chloride — AgCl. — A white, curdy precipitate," 9 - insolu- 
ble in acids, but freely soluble in ammonium hydrate, may be 
made by adding a chloride to a silver solution, thus : — 
AgNO a + HC1 = AgCl 4- HN0 3 . 

Silver Bromide — AgBr is a similar precipitate, 293 except that it 
is yellowish-white and much less readily soluble in ammonium hy- 
drate, and is made by adding a bromide to a silver solution, thus : — 
AgN0 3 + KBr =/*gBr r KN0 3 . 

Silver Iodide is precipitated - 9 - on mixing an iodide solution 
and a silver solution (AgN0 3 "r- Kf = Agl + KN0 3 ) and is yellow 
and insoluble in ammonium hydrate. 

Effects of Light. — Light decomposes salts of silver, especially if 
organic matter be present, depositing metallic silver in a fine, 
black powder, hence their uses in photography, and in making in- 
delible inks, hair dyes, etc. The black stain of silver on the 
hands or clothes i8T may be removed by potassium cyanide or by 
applying tincture of iodine and washing in ammonia-water. When 
persons have taken silver salts for a long time, it sometimes 
occurs that the tissues, especially the skin, are permanently dark- 
ened. This is due to the decomposition of the silver salt under 
the influence of organic matter and light. 

292 HC1 and note white precipitate of AgCl, soluble in XH t HO. 

293 KBr and note yellowish-white precipitate of AgBr, slightly soluble in 
NH 4 HO. 

294 KI and note yellow precipitate of Agl, insoluble in NH 4 HO. 

295 Repeat tests 292, 293, 294, but instead of XH 4 HO add sodium hypo- 
sulphite and note how readily all three precipitates dissolve. 



128 ESSENTIALS OF CHEMISTRY. 

Photographic " sensitized " plates, papers, etc., are generally 
coated on one side with a film of collodion, gelatine or albumen 
in which is precipitated in the dark, a fine deposit or "emulsion " 
of silver chloride, bromide or iodide. On the least exposure to 
light, and in proportion to such exposure, the molecules of these 
silver salts are so disturbed that when subjected to the action of 
a reducing agent ("developer") in the dark-room they decom- 
pose, depositing black metallic silver. As soon as the plate is 
sufficiently developed, it is dropped into a solution of sodium 
hyposulphite, which dissolves out all the unreduced silver salt' 293 but 
not the black deposit of metallic silver, and the plate is said to be 
"fixed " as there is no more silver salt in it to blacken it further. 

Poisoning occurs mostly from swallowing the nitrate, which is 
the only soluble silver salt. It is a severe corrosive poison, de- 
stroying the tissues by coagulating their albumin. Its best anti- 
dote is a soluble chloride, as common salt, which forms the insol- 
uble silver chloride. Albumin is also a good antidote. 

GOLD occurs widely, but sparingly distributed ; always free, 
mixed with sand and quartz, fwDm which it is separated by agita- 
tion with water or by dissolving it out with mercury. It is a soft, 
bright, yellow metal ; so malleable that it may be beaten into 
sheets (gold leaf) less than one two-hundred- thousandth of an 
inch in thickness. These transmit green light. 296 For coinage 
and general use gold is usually hardened by the addition of cop- 
per or silver, the amount of which is indicated by the term carat 
fine. Thus, pure gold is twenty-four carat, and eighteen, sixteen, 
and twelve carat signify so many twenty- fourths of pure gold. 

Gold does not tarnish in the air ; is unaffected by alkalies or 
any single acid, 297 but nitro-muriatic acid (aqua regia) easily dis- 
solves it, 298 forming auric chloride, a salt that is easily decom- 

296 Gold. Metal. After noting the physical properties of a sheet of gold- 
leaf, lay it between two glass slides, hold it before a strong light and note that 
it is translucent and green. ( 297 ) Divide it in two portions, and drop one into 
HN0 3 and the other into HC1 in separate beakers. Note that neither acid 
affects the gold. (* 98 ) Pour the contents of one beaker into the other and 
note that the gold dissolves. 



PART I. INORGANIC CHEMISTRY. 129 

posed by heat, light, organic matter and various chemicals, 298 with 
the deposition of metallic gold in fine powder as in '"toning" 
photographic prints. With stannous chloride it yields a beauti- 
ful precipitate (purple of Cassius) used in ornamenting porcelain 
and glassware. 

The "Auri ei Sodii Chloridum" U. S. P. ( AuCl ...XaCl, is some- 
times given in doses of .005 Gm. ( ^ gr.) as a nerve tonic and 
stimulant in functional impotence and in some of the "gold 
cures " for inebriety. 

PLATINUM occurs free, associated with the allied metals, 
palladium, rhodium, ruthenium, osmium and iridium. Owing to its 
scarcity it is almost as costly as gold. Resembles silver in appear- 
ance ; m can be melted only with very great difficulty, and very few 
substances corrode it ; hence it is used to make vessels that are 
to be exposed to very high heat or to contain corrosive chemicals. 
Platinum wire is also used in flame testing. 

Platinum readily dissolves in nitro-muriatic acid, forming 
platinic chloride, PtCl 4 , a valuable reagent for potassium, ammon- 
ium and alkaloids." " 

The other members of this group are rare elements found in 
small quantities in certain platinum ores. Iridium is used in the 
hard tip of gold pens and is often added to platinum to increase 
its hardness and resistance to chemical agents. Osmium and 
palladium compounds are sometimes used as chemical reagents, 
and osmic acid (osmic anhydride, Os0 4 ) is much employed as 
a stain in histology. 



299 To a gold solution (AuCl,) in a test-tube add FeS0 4 and set aside; a 
yellow lustrous deposit of gold is precipitated on the inside. 

300 To some AuCL, solution add a bit of tin-foil and note the formation of 
the " purple of Cassius." 

301 Platinum. Metal. Note the physical properties of the metal by exam- 
ining the mounted platinum wire kept on the desk. 

302 Compound. To a few drops of a platinum solution add a drop of potas- 
sium or ammonium solution and note the creamv precipitate of K 9 PtCl 6 or 
(XH t ). 2 PtCl,, 

303 j Q a platinum solution add a few drops cf potassium iodide, and note 
the dark-red color, giving place to a black precipitate on heating. 



13° 



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PART II.— ORGANIC CHEMISTRY. 



Organic Chemistry is the chemistry of the compounds of car- 
bon, and this chapter may be considered a resumption of the 
study of that element. The name " organic " is a relic of an old 
misconception. 

Centuries ago it was observed that substances produced by, and 
composing living organisms differed remarkably from those of 
mineral origin ; they were subject to decay, fermentation and 
putrefaction, and when burned left no residue except such mineral 
matters as were incidentally incorporated. Having never seen 
them produced except under the influence of organized life, the 
older observers assumed that they could not be formed otherwise, 
and called them u organic." But in 1828, Woehler made urea 
from ammonium cyanate, and soon after Kolbe made acetic acid 
from materials as plainly mineral. Since that time artificial pro- 
ducts, many of them unknown in nature, have become so numerous 
and complex that it now seems possible to duplicate artificially 
any organic substance, especially if its chemical constitution be 
known. However, chemistry has not, and probably never will, 
produce an organized body, i. e. 9 one having an anatomical, cellu- 
lar structure. Such structures must live and grow; their study is 
the orifice of physiological chemistry. 

Carbon is the constant and characteristic constituent of all the 
organic compounds, and is responsible for their vast number and 
great complexity. Though carbon forms compounds of infinite 
number and extreme complexity, it is with the aid of a very few 
other elements, viz : hydrogen, oxygen, nitrogen, and occasion- 
ally sulphur, phosphorus and iron, sometimes others ; but the 
larger number of even the artificial compounds contain only the 
above-named elements. This is due to the fact that the carbon 
atoms possess, in the highest degree, the power of combining with 

(*33) 



134 ESSENTIALS OF CHEMISTRY. 

each other and interchanging valences, forming groups or chains 
around which the other elements are arranged. But for this power 
carbon could form only one saturated compound with hydrogen, 
CH 4 . Carbon being quadrivalent, the compounds C 2 H 6 and C 3 H 8 
would be unsaturated. Experiment, however, proves that they 
are saturated compounds. The .explanation is that the carbon 
atoms combine with each other, mutually neutralizing one or more 
valences, thus : — 

H H H H H H 

I I I III 

H— C— H; H— C— C— H; H— C— C— C— H. 

I II ill 

H H H H H H 

It will be observed that these formulae have a common dif- 
ference of CH 2 . They are said to form a hoiiiologous series. 
When the carbon remains the same but the hydrogen differs by 
H 2 , the series is said to be is o logons. 

In the following examples each vertical column represents a 
homologous, each horizontal line an isologous series : — 

C H 4 — -Methane C H 2 — Methene C — Methine 

C 2 H 6 — Ethane C 2 H 4 — Ethene C 2 H. 2 — Ethine 

QH b — Tritane 0***6 — Tritene C 3 H 4 — Tritine 

C t II 10 — Tetrane QH 8 — Tetrene Q±H 6 — Tetrine 

C 6 H 12 — Pentane C 5 H 10 — Pentene C 5 H& — Pentine. 

Without this arrangement in series, it would be almost impos- 
sible to remember the composition of organic substances. 

In systematic works on organic chemistry, these series form the 
basis of classification ; but as this would necessitate mentioning 
thousands of bodies of no medical interest, it would be imprac- 
ticable in a work like this ; and after all, no system of classification 
yet devised is perfectly satisfactory. We shall therefore adopt 
the following : 

Hydrocarbons and their derivatives. Organic acids. 

Alcohols. Carbohydrates (sugars and starches). 

Ethers (including oils and fats). Glucosides. 

Aldehydes. Ammonium substitution products. 

Natural alkaloids. 



PART IT. — ORGANIC CHEMISTRY. 1 35 

The ultimate analysis of a carbon compound resolves itself into 
the determination of the presence and quantity of carbon, hydrogen 
and oxygen, and since many of these compounds, especially those 
from the animal and vegetable kingdom, contain nitrogen, and at 
times also sulphur, phosphorus and iron, their presence must also 
be proven, and quantity estimated. 

The determination of the quantity of oxygen is so difficult, and 
the process so complicated, that it is usually computed by differ- 
ence after the other elements have been quantitatively calculated. 

Deier?nination of carbon. — Carbon is known to be present 
when a substance chars on igniting it away from air. The 
quantity of carbon is estimated by combustion, whereby the car- 
bon unites with oxygen to form carbon dioxide — COo. In the 
same experiment the hydrogen unites with oxygen to form water 
H 2 0, and we thus estimate quantitatively the hydrogen present.^ 04 

Deter?nination of Nitrogen. — Heat the substance in a test- 
tube. A pungent odor like that of burnt feathers indicates the 
presence of nitrogen, as does the odor of ammonia when a fixed 
alkali is also added/' 05 

The amount of nitrogen is estimated by collecting and measur- 
ing the ammonia. 

Determination of Sulphur. — To the substance in a test-tube 
add solid KHO, which, with the sulphur, yields potassium 



30 * Mix the substance under examination with copper oxide and heat in a 
hard-glass tube. Draw the products of this combustion through a series of 
tubes containing dried, granulated calcium chloride, which will absorb the 
water, and through a second vessel (a Liebig bulb) containing potassium 
hydrate, which absorbs the carbon dioxide. The vessels containing the cal- 
cium chloride and potassium hydrate are each separately weighed, before and 
after the combustion, and the difference in weight represents the amount of 
water and carbon-dioxide present. From these weights the carbon and 
hydrogen are readily estimated. 

05 To the substance to be examined in a test-tube add some metallic potas- 
sium, and heat. Potassium cyanide is formed. Add water, and filter. To the 
filtrate add ferrous sulphate containing a little ferric salt, and then several 
drops of KHO. Heat again and add HC1 in excess. A precipitate of 
Prussian-blue indicates nitrogen. 



I36 ESSENTIALS OF CHEMISTRY. 

sulphide. Dissolve in a little water, a drop of which, on a clean 
piece of silver, makes a black stain of Ag^S. 

Determination of Phosphorus, — (Method of Carius.) Oxidize 
the substance by heating it with nitric acid in a sealed tube. If 
phosphorus be present phosphoric acid is formed, and may be 
recognized by the tests already given for the phosphates. 

Determination of Chlorine, Bromine and Iodine,, — They may 
be detected by heating the substance with lime, dissolving in 
water, acidifying with nitric acid and testing the filtrate by the 
appropriate tests. 307 

Molecular Formula. — The analysis of a substance shows only 
its percentage composition ; the formula must be deduced by 
dividing the percentage of each element by its atomic weight to 
show how many atoms it represents and then making the formula 
to correspond to these ratios. For instance, acetic acid shows 
this percentage composition — Carbon, 40.00 ; Hydrogen, 6.66 ; 
Oxygen, 53.34. 

40.00 -5- 12 = 3.33 atoms of Carbon. 
6.66 -^ \-~ 6.66 atoms of Hydrogen, 
53.34 -^ 16 = 3.33 atoms of Oxygen. 

These ratios are seen to bear to each other the proportion of 
one of carbon, two of hydrogen, and one of oxygen; hence the 
formula, CH 2 0. But formaldehyde, lactic acid and several other 
substances show the same percentage composition. We would 
thus be still left in doubt as to the correct formula of each were 
it not for a knowledge of their respective molecular weights, as 
shown by their " vapor densities." Since we know that 30 is the 
molecular weight of formaldehyde ; 60 of acetic acid and 90 of 
lactic acid; and that CH 2 (12 + 2+16) represents a molecular 

: ' 0B Add KHO to lead-acetate solution until the precipitate first formed is 
redissolved. In this boil the sulphurized organic substances (e.g., albumin) 
and note the blackening by the PbS formed. 

?(il A delicate test is to place some cupric oxide on a platinum wire, and 
keep it in the flame until it appears colorless. Place a little of the substance 
under examination on the cupric oxide, and heat in the non-luminous gas 
flame, when the presence of either chlorine or bromine will be indicated by 
an intense greenish-blue color. 



PART II. ORGANIC CHEMISTRY. 



137 



weight of 30, we see that CH 2 = formaldehyde : C 2 H 4 0, = acetic 
acid, and C 3 H fi 3 == lactic acid. 

The above are empirical formulae since they show only the num- 
ber and kind of atoms composing the molecule. The rational 
formula aims to show also the constitution of the molecule, the 
arrangement of its atoms into radicals. Thus in acetic acid one 
atom of the hydrogen plays the part of the positive radical ; while 
the other atoms of the molecule form its negative radical ; so the 
rational formula is HC 2 H 3 2 . 

Isomerism. — Two or more substances are said to be isomeric 
when they have the same empirical but different rational formulae, 
differ in chemical properties and are hence distinct substances, 
e.g., aldehyde, C 2 H 4 or CH 3 -CO-H: and ethylene oxide, 
C 2 H 4 or CH 2 -0-CH>. Substances whose formulae are simple 
multiples of each other are said to be polymeric, e. g., formalde- 
hyde (CH 2 0), acetic acid (C 2 H 4 Q 2 ) and lactic acid (C 3 H 6 3 ). 
When elements manifest this same quality it is called allotropism ; 
of which we have already noticed instances in coal, graphite and 
diamond, and in ordinary oxygen and ozone. 

Hydrocarbons. 

Hydrocarbons are compounds of carbon with hydrogen only. 
They are exceedingly numerous and are regarded as derived from 
CH± in homologous and isologous series. The following table 
shows the usual classification : 



Series 


Radicles 


Series 


Radicles 


Series 


Series 


1 
Gen. 


Gen. 


2 
Gen. 


Gen. 


3 
Gen. 


4 
Gen. 


Formula 


Formula 


Formula 


Formula 


Formula 


Formula 


CnH2n — 2. 


CnH2n — 1. 


CnH2n. 


CnH2n — 1. 


CnH2n — 2. 


CnH2n — 4. 


Valence 


Valence 


Valence 


Valence 


Valence 




O 


I 


II 


III 


IV 




Methane. 


Methyl. 


Methene. 


Methenyl. 


Methim 




CH 4 


CH 3 


CH 2 


CH 


C 




Ethane. 


Ethyl. 


Ethene. 


Ethenyl. 
C0H3 


Eihine. 


Ethone. 


C 2 H a 


C. 2 H 5 


C 2 H 4 


C 2 H 2 


C 2 


Triiane. 


Trityl. 


Tritene. 


Tritenyl. 


Tritine. 


Tritone. 


C 3 H 8 


C 3 H 7 


C 3 H 6 


C 3 H 5 


C 3 H 4 


C 3 H 2 


Tetrane. 


Tetrvl.' 


Tetrene. 


Tetrem 1. 


Tetrine. 


Tetrone. 


C 4 H 10 


C/H 9 


C 4 H S 


C 4 H' 7 


C 4 H 6 


C 4 H 4 


Pentane. 


Pentyl. 


Pent-ene. 


Pentenvl. 




Pentone. 


C 5 H 12 


C,H 1X 


C 5 K 10 


c 5 h; 


C 5 H 8 


C 5 H 6 


Hexane. 


Hexyl. 


Hexene. 


Hexenyl. 


Hexine. 


Hexone, 


C 6 H 14 


C6-H-13 


C 6 H 12 


C 6 Hn 


C 6 H 10 


C 6 H S 


etc. 


etc. 


etc. 


etc. 


etc. 





Tritune. 

Tetrune. 

C 4 H 2 
Pen tune. 

C 5 H 4 
Hexune. 

C 6 H 6 



IO 



138 ESSENTIALS OF CHEMISTRY. 

The nomenclature is systematic, but has never been fully 
adopted. The root of each name is from a Greek numeral and 
indicates its position in homologous series, while the final vowel 
indicates its position in isologous series. By successive abstrac- 
tions of an atom of hydrogen are formed several series of organic 
radicles, the valences of which depend on the number of atoms 
abstracted, and thus increase in isologous series. They are given 
the general termination of "-yl." Being positive, these radicles 
combine with negative radicles, just as do K, Na or NH 4 , and 
form analogous compounds. 

Methane Series, sometimes called the Paraffins {parum, too 
little and affinis, having affinity) on account of their lack of affin- 
ity for chemical reagents, is a class of hydrocarbons derived in 
homologous series from CH 4 . Being fully saturated, they are 
very stable and indifferent to chemical reagents, unaffected usu- 
ally by either acids or alkalies. The natural, crude Petroleum is 
a mixture of mainly these various hydrocarbons 30S as far down as 
the sixteenth (C 16 H 34 ). On account of their boiling-points vary- 
ing with their molecular weights, they can be more or less com- 
pletely separated by fractiomal distillation, those having the light- 
est molecules passing over first. As all the lighter ones are liable 
to give off vapors that when mixed with air are explosive, it is 
forbidden in most states to sell, for use in ordinary lamps, an oil 
that " flashes" below 100 F., or itself ignites below 300 F. Of 

308 Cymogene, boils about 32 F.; used in ice-machines. 

Rhigolene, boils about 65 F.; as a spray for local anaesthesia. 

Petroleum Ether, boils about ioo° F.; used as a solvent and for "air-gas." 

Gasolene, boils about 120 F; used as a solvent and for " air-gas." 

Naphtha, A, B and C, boils 180 to 3CO L ' F.; used as a solvent for fats, etc. 

Benzine, boils about 150 F. ; used as solvent in varnishes and paints. 

Kerosene, boils about 350° F. ; used in ordinary lamps. 

Mineral Sperm oil, boils about 425 F.; used for lubricating machinery. 

Lubricating oil, boils about 575° F.; used for lubricating machinery. 

Petrolatum, U. S. P., used in ointments, etc. 

Parafnne, used in candles. 

* 09 Into a large test-tube pour about 20 Cc. of cheap kerosene, insert a ther- 
mometer and a bent glass tube. Apply a heat so gently that the temperature 
rises only about a degree a minute. At frequent intervals blow through the 
glass tube and make a foam on the surface of the oil and apply a flame to the 
mouth of the test-tube. When the flame flashes down the tube note the read- 
ing of the thermometer and regard that as the " flashing-point." 



PART II. — ORGANIC CHEMISTRY. I 39 

the commercially separated products the Pharmacopoeia recog- 
nizes as officinal Benzine or petroleum ether, a colorless, volatile 
liquid ; Petrolatum Liquidum, a tasteless, oily liquid, called also 
albolene ; Petrolatum Molle, the soft vaseline, and Petrolatum 
Spissum, the harder vaseline. 

Methane (CH 4 ) is a light, colorless gas, occurring in illumi- 
nating gas formed from the destructive distillation of coal : in 
coal mines as "fire damp," where it often causes frightful explo- 
sions ; from decomposition of vegetable matter under water, 
where as "marsh-gas" it may be seen bubbling up, especially 
when the mud is stirred ; in natural gas, of which it constitutes 
over 90 per cent. CH 4 is the starting point for the synthetical 
production of many other organic compounds, and may itself be 
made artificially from ethine (acetylene), which is made from the 
minerals, calcium carbide and water. 810 

Ethane (C 2 H 6 ), Tritane or propane (C 3 H 8 ), and Tetrane or 
butane (C 4 H 10 ), escape when crude petroleum is heated. These 
gases are collected, condensed into a liquid, and sold as cymo- 
gene for ice making. 

Methene Series. — These were formerly called " olefins," be- 
cause the first member, Ethene (C 2 H 4 ), happens to form an oily- 
liquid with chlorine, and was named "defiant gas." Ethene is 
formed in the destructive distillation of coal, and is the most 
valuable constituent of illuminating gas, where it is called "heavy 
carburetted hydrogen." Being unsaturated the olefins are 
readily attacked by reagents, especially the acids. 

Ethine Series. — These too are unsaturated , they act as 
bivalent or quadrivalent radicles. 

Ethine or acetylene (C 2 H 2 ) is the most important member and 
enjoys the distinction of being one of the few, if not the only, 
hydrocarbon made by the direct union of its elements. It may be 
produced by the electric arc between carbons in an atmosphere 

310 Heat in a test-tube a mixture of 4 parts cf sodium acetate, 4 parts of 
XaHO and 6 parts of lime; collect the gas; it is methane. 



140 ESSENTIALS OF CHEMISTRY. 

of hydrogen. It is now made industrially as an illuminant, from 
calcium carbide 311 and water ; thus, CaC 2 f 2H 2 = Ca(HO) 2 + 
C 2 H 2 . It is very rich in carbon (92.3 per cent.) and burns with 
a very pure white flame of dazzling brilliancy. 

Tritone Series or Terpenes. These- are unsaturated and 
either univalent or bivalent and combine readily with the nega- 
tive radicals. The series begins with Tritone (C 3 H 2 ), but it is the 
eighth member, Decone or Terpene (C 10 H 16 ) that possesses most 
medical interest, as this formula represents the composition (iso- 
meric) of most of the volatile or essential oils, such as those of 
lemon, orange, cloves, pepper, lavender, bergamot, etc. 

Volatile oils are found in plants, especially in the flowers, of 
which they are usually the odorous essences (hence called also 
essential oils). They are obtained by distillation, are very slightly 
soluble in water (aquae), but quite soluble in alcohol (spiritus). 
A cologne is an alcoholic solution of an assortment of volatile 
oils. 

Turpentine (oleum terebinthinae, U. S. P. obtained from Pinus 
Australis) is the most important of the volatile oils ; obtained as a 
resinous juice from various coniferae, and may be taken as a type 
of the class. It is a thin colorless liquid, a valuable solvent of 
oils and resins ; absorbs oxygen and stores it up as ozone, gaining 
thereby oxidizing, antiseptic and disinfectant properties. By the 
action of concentrated sulphuric acid, turpentine is changed into 
terebene (Ci H 16 ), a valuable remedy for bronchitis and flatulence. 

Resins and Camphors. On exposure to air the terpenes 
oxidize with the production of resins and camphors, whose for- 
mula is C 10 H 16 O. 

Resins are a numerous class, many of which are true acids or 
mixtures of acids. They are soluble in alcohol but insoluble in 
water except by the intervention of an alkali with which they will 

311 Calcium Carbide, CaC 2 . The manufacture of this recently discovered 
article is remarkably simple and cheap. When a mixture of lime and coke 
are placed in the electric furnace they fuse into a dark gray crystalline mass 
on which the heat has no further effect. This calcium carbide is packed for 
the market in sealed cans to protect it from the water of the air. 



PART II. ORGANIC CHEMISTRY. 141 

unite to form soluble soaps. The official resin (resina, U. S. P.) 
is formed by the oxidation of turpentine as it exudes from the 
pine trees. 

Solutions of shellac, mastic, copal and others are used as var- 
nishes. In the natural state, resins are usually mixed with other 
substances. Mixed with volatile oils they form oleo- resins and 
balsams, e. g., benzoin, tolu and balsam of Peru ; and with gums, 
gum resins, e. g., ammoniac, myrrh and asafoetida. 

Camphors, sometimes called stearoptens. — These are white, 
crystalline, volatile solids of an agreeable, pungent odor ; slightly 
soluble in water (aqua camphorae), freely soluble in alcohol 
(tinctura camphorae) ether and oils. 

Common Camphor is derived from the leaves and branches of 
the camphor laurel of China and Japan. It is much used ; inter- 
nally, as a stimulant, diaphoretic, carminative and expectorant, 
and externally, as an antiseptic and analgesic. 

Monobromated Camphor, C 10 H 15 BrO, is made by adding bromine 
to a solution of camphor in chloroform, the bromine displacing 
one atom of hydrogen. It is more sedative than ordinary 
camphor. 

Menthol is the camphor of oil of peppermint, and has its odor. 
It is much more analgesic than common camphor. 

Thymol is the camphor of oil of thyme and of horsemint. It is 
a stronger antiseptic than carbolic acid, and withal has a pleasant 
odor. 

Caoutchouc or India-rubber (Elastica U. S. P.), and gutta- 
percha. These are terpenes, which, insoluble in water, occur 
suspended in the milky juice of certain tropical plants. Caout- 
chouc is soft and elastic ; gutta-percha is hard and brittle. Both 
can be vulcanized (combined with sulphur), the hardness, etc., 
depending on the amount of sulphur and heat used ; so that many 
valuable articles are made from them. Caoutchouc dissolves in 
petroleum-ether and carbon disulphide \ gutta-percha dissolves 
best in chloroform (liquor gutta-perchae). 

Benzene Series. So named because they are all derived from 



142 ESSENTIALS OF CHEMISTRY. 

Benzene (Hexune) C 6 H 6 , and are also called " aromatic" because 
of their aromatic odor and taste. 

Benzene™ must not be confounded with benzine, one of the 
petroleum products. Benzene is distilled from coal-tar and is a 
colorless, volatile liquid of a peculiar odor, and a valuable solvent. 
It is especially interesting to the chemist for the great number 
and diversity of its derivatives. Treated with strong nitric acid, 
it yields Nitrobenzene or oil of mirbane™ a very poisonous sub- 
stance used as a cheap perfume, especially in soaps. 

Toluene (heptune), C 7 H 8 , is another member of -this series, but 
of little medical interest, except sometimes used locally in diph- 
theria. 

Naphthalene is the so-called " coal-tar camphor," and is em- 
ployed in the form of moth-balls. 

Halogen Derivatives of the Hydrocarbons. The hydrogen 
in the hydrocarbons is replaced by the halogens, viz., by chlorine, 
bromine, and iodine, forming halogen derivatives. They are for 
the most part colorless, ethereal smelling liquids, insoluble in 
water. If nascent hydrogen is allowed to act upon these deriva- 
tives, it combines with the halogen atom and returns the deriva- 
tives to their previous state, thus, CHC1 3 + 3H 2 = CH 4 -f 3HCI. 

Chloroform (trichlormethane) CHC1 3 is made 314 by distilling 
a strong solution of chlorinated lime and ordinary alcohol. Of 
late it is being manufactured more economically by a patented 
process from acetone, a bi-product in certain manufactures. 
Chloroform is a colorless, volatile liquid of a sweetish taste and 
an agreeable, ethereal odor. It is heavier than water and does 
not dissolve in it, but soluble in alcohol and ether. It is a sol- 
vent for phosphorus, iodine, india-rubber, the alkaloids, and 

312 Benzene. Heat a mixture of dry benzoic acid and quicklime and pass 
the vapor of the benzene evolved into a test-tube set in ice, Fig. 26. 

313 Nitrobenzene. Mix two parts of H 2 S0 4 and one of HN0 3 : let cool. Add 
benzene a drop at a time, shaking and cooling each time until I or 2 Cc. are 
added. Then pour into water and note the " essence of mirbane " sinking as 
a brownish-yellow oil to the bottom. 

iU Chloroform. In the apparatus shown in Fig. 26 distil 5 Gm. of chloral 
covered with KHO solution, and examine distillate for chloroform. 



PART n. — ORGANIC CHEMISTRY. 1 43 

many other substances. Its vapor is heavier than air, but is not 
easily ignited. Yet it should not be administered it too near a 
flame, for fear of the poisonous, irritating fumes from its decom- 
position. 

Chloroform is sometimes given by the stomach as a sedative 
but most frequently administered by inhalation as an anaesthetic, 
for which purpose it should be of undoubted purity. 

Test of Purity : — Pure chloroform is not colored by an equal 
volume of pure sulphuric acid ; the specific gravity should not be 
below 1.480. 

If chloroform be taken by the stomach, it being almost insolu- 
ble, is absorbed very slowly, and its principal action is the local 
irritation of the mucous surfaces. Recovery has followed a dose 
of four ounces, and death has been caused by one drachm taken 
into the stomach. The vapor acts more energetically and seems 
to owe its potency for evil to its paralyzing influence on the nerve 
centers, especially these of the heart. For this reason chloroform 
should never be administered except by a capable physician, It 
should be well diluted with atmospheric air. However, death has 
occurred from the inhalation of moderate quantities of chloroform 
properly diluted and at the hands of careful physicians, and where 
the autopsy revealed no heart lesion. There is no chemical anti- 
dote for chloroform. When it has been swallowed evacuate the 
stomach ; when inhaled, lower the head, give fresh air, employ 
artificial respiration, apply the induced current, and administer 
hypodermic injections of strychnine and whiskey. Chloroform 
should be kept in dark amber-colored bottles, and carefully corked 
to prevent evaporation. 

In cases of intentional poisoning by chloroform the odor of the 
chemical is usually sufficient for recognition. 

Bromoform — CHBr b — is a colorless liquid of agreeable odor, 
formed by the action of bromine and potassium hydrate upon al- 
cohol. It has been used as an anaesthetic, the advantage claimed 
being that both pulse and respiration remain about normal, even 
in prolonged narcosis. It is a valuable sedative in whooping 



144 



ESSENTIALS OF CHEMISTRY. 



cough. It is, however, poisonous when taken internally in large 
amounts. In the case of two children, one four, the other four 
and one-half years old, recovery is reported after the ingestion of 
about 20 grains. In both cases ether and camphor were injected 
hypodermically to antagonize the bromoform. 

Iodoform — CHI 3 — is formed by the action of iodine and potas- 
sium hydrate on ordinary alcohol. It is a yellow, crystalline body, 
soluble in alcohol and ether, but insoluble in water. In spite of 
its disagreeable odor it is much used for its antiseptic effects — 
effects due not to the iodoform as such, but to traces of iodine 
liberated in its decomposition by the living tissues. The other 
therapeutic properties of iodoform are alterative, anaesthetic and 
anti-tubercular. 

Alcohols and their Derivatives. 

An alcohol is generally regarded as the hydrate of a hydrocar- 
bon radical since its formula always has a hydrocarbon radical at 
its positive end, and the radical HO at the negative end. It might 
be regarded as formed by substituting the radical HO for an atom 
of hydrogen in the molecule of a saturated hydrocarbon : and 
again from H 2 in which one atom of hydrogen is replaced by 
a hydrocarbon radical. 

Methyl Series. — The alcohols of most interest to the physician 
are those of the Methyl series ot hydrocarbon radicals. They are 
often called the monatomic alcohols because all this series of radi- 
cals are univalent (monad.) The following table shows a few of 
them and their derivatives : 









Examples of Com- 












pound Ethers. 






Radicals. 


Alcohols 

(Hydrates). 


Ethers 
(Oxides) . 




Alde- 
hydes. 


Acids. 
















Nitrates. 


Sulphates. 






Methyl, CH 3 


CH 3 HO 


(CH 3 ) 2 


CH 3 N0 3 


(CH,)oS0 4 


CHoO 


CH 2 2 


Ethyl, C,H, 


C 2 H 5 HO 


(C„H 5 ) 2 


C,H 5 N0 3 


(C 2 H 5 )„S0 4 


CoH 4 


CoH 4 Oo 


Propyl, C 3 H 7 


C3H.HO 


(C 3 H 7 ) 2 


C 3 H 7 N0 3 


(C 3 H 7 ) 2 S0 4 


C 3 H«0 


C 3 H G 2 


Butyl, C 4 H 9 


C 4 H 9 HO 


(C 4 H 9 ) 2 


C 4 H 9 N0 3 


(C 4 H 9 ) 2 S0 4 


C 4 H s O 


C 4 H 8 2 


Amyl. C 5 H tl 


C 5 H n HO 


(C B H 1]L ) 2 


CsH^NOg 


(C 5 H X1 ) 2 S0 4 


C B H 10 


C 5 H 10 O 2 


Hexyl,C 6 H 13 


C 6 H 13 HO 


(C 6 H 13 ) 2 


C 6 H 13 N0 3 


(C 6 H 13 ) 2 S0 4 


C 6 H 12 


^6^-1 2^2 


etc. 


etc. 


etc. 


etc. 


etc. 


etc. 


etc. 






PART II. — ORGANIC CHEMISTRY. 1 45 

In the formation of these compounds the starting point is not 
the radicals, but their hydrates, the alcohols. When an alcohol 
is oxidized with a limited supply of oxygen, two atoms of hydro- 
gen are removed and no oxygen is added. This forms the alde- 
hyde, thus : 

Methyl Methyl 

Alcohol. Aldehyde. 

CH3HO + O = CH 2 + H 2 0. 

If there is a full oxidation, an atom of oxygen takes the place of 
the two atoms of hydrogen removed, and forms the corresponding 
acid, as — 

Methyl Formic 

Alcohol. Acid. 

CH 3 HO + 2 = CH 2 2 + H 2 0. 

In the formation of aldehydes and acids the radical supplies 
part of the hydrogen removed and loses its identity. As part of 
the hydrogen in an acid forms the positive radical it is written 
first ; e. g., formic acid is written HCH0 2 , (rational formula) in- 
stead of CH 2 (X (empirical formula). The various other com- 
pounds of these radicles are called ethers ; the oxides being called 
simple ethers, the others compound ethers. They are generally 
formed by treating the appropriate alcohol with the appropriate 
acid. 

A Ketone is an organic compound consisting of the unsaturated 
radicle "CO " united to two univalent radicles, as in (CH 3 ) 2 CO, 
dimethylketone, commonly called aceto?ie. 

Methyl Alcohol — (CH 3 HO), the so-called wood spirit, wood 
naphtha, wood alcohol, or pyroligneous spirit, is obtained from the 
destructive distillation of wood; it does not exist in nature. 
When pure it resembles ordinary alcohol in its properties and 
physiological action, but the commercial article has a disagreeable 
odor and taste from the presence of tarry matters, etc. It is not 
used in medicine, but is employed widely in the arts as a substi- 
tute for ordinary alcohol, which, though cheaper to manufacture, 
cannot be sold as cheaply because of the tax imposed on alcoholic 



146 ESSENTIALS OF CHEMISTRY. 

beverages. In England ordinary alcohol is relieved of this tax 
and made available to the arts by mixing with it 10 per cent, of 
commercial methylic alcohol, which makes it unfit to drink. 

Ethyl alcohol, C 2 H 5 HO, also called spirits of wine, vinic alco- 
hol and alcohol, is obtained in the spirituous fermentation of sev- 
eral varieties of sugar, such as grape-sugar, maltose, etc. 

Glucose. Alcohol. Carbon dioxide. 

C 6 H 12 6 - 2C 2 H 5 HO + 2C0 2 . 

Liquids (wines, etc.), containing alcohol, have been known and 
used as beverages from the remotest antiquity. 

From these the alcohol is separated by distillation, for being 
more volatile than the water it passes over first. 815 Commercial 
alcohol always contains water, and when pure, or " absolute " alco- 
hol is required, the commercial article is mixed with some sub- 
stance, which is very avid of water (as quick lime), and then again 
distilled. Ethyl alcohol may also be obtained experimentally from 
ethyl chloride (C 2 H 5 C1), bromide (C 2 H 5 Br), or iodide (C 2 H 5 I), 
by replacing the halogen with HO. This is best accomplished 
by the agency of freshly precipitated silver oxide and water (prac- 
tically silver hydrate) in the presence of heat, thus : C 2 H 5 Br + 
AgHO = C 2 H 5 HO + AgBr. 

Alcohol is a light, colorless liquid of a pleasant, pungent odor 
and burning taste. It has great affinity for water, which fact 
probably accounts for its preserving animal tissues and coagulat- 
ing the albuminoids. At minus 194 F. it is a thick liquid and at 
minus 266 F. a solid white mass. It boils at 173. 6° F. 

Test for Parity. — Absolute alcohol is soluble without turbidity 
in a small amount of benzene. If 3 per cent, or of more water is 
present in the alcohol cloudiness appears on adding the benzene. 

Analyses for traces of alcohol in a solution are best made by 
oxidizing the alcohol into an aldehyde, or by converting the alco- 

815 Alcohol. Distil some wine in apparatus shown in Fig. 26 [side neck 
test-tube distilling apparatus] and test distillate for alcohol by odor, taste and 
iodoform test. 






PART II. ORGANIC CHEMISTRY. 1 47 

hol, by means of dilute KHO (or NaHO) and iodine, into iodo- 
form." 16 

It is largely used in the arts and in pharmacy, principally as a 
solvent ; and also in the manufacture of various substances, as 
vinegar, chloral, chloroform, iodoform, ether, etc. ; as a fuel when 
a hot and smokeless flame is needed and as a menstruum in 
the preparation of tinctures and spirits. Alcoholic solutions of 
fixed medicinal substances are called " tinctures ;" those of vola- 
tile principles, " spirits." Alcohol is used in many forms and of 
various degrees of concentration. Absolute alcohol is rarely em- 
ployed, except in chemical analyses. Alcohol, U. S. P., is the 
ordinary rectified spirit, and contains 91 per cent, of alcohol. 
Alcohol dilulum, U. S. P., diluted alcohol, is made by mixing 
water and alcohol equal parts. Spiritus frumenti, U. S. P., 
whisky, and spiritus vini gallici, U. S. P., brandy, are obtained by 
distillation ; the former from fermented grain, and the latter from 
fermented grape juice. They contain about 50 per cent, of 
alcohol. Both are colored by the addition of caramel (burnt 
sugar). Their flavor is due to small quantities of other alcohols, 
produced in the fermentation, and to certain ethers formed from 
these alcohols, especially as the liquor " ages." A large class of 
alcoholic beverages are made by fermenting various liquids con- 
taining sugar or some substance capable of conversion into sugar. 

Beer, ale and porter are infusions of malted grain fermented 
and flavored with hops. They, therefore, contain the soluble 
constituents of the grain. Their alcoholic strength is about 5 per 
cent. Wines are prepared by allowing grape juice to ferment. 
Various wines are used but the pharmacopoeia recognizes only 
two classes, White and Red, each with an alcoholic strength of 10 
to 14 per cent. Cider is the fermented juice of the apple and 
contains about 5 per cent, of alcohol. It is very prone to acetous 
fermentation and liable to produce colic and diarrhoea. 

316 Warm the solution supposed to contain alcohol; add a few scales of 
iodine, and then caustic potash until the color is discharged. On cooling, 
yellow scales of iodoform are deposited. 



148 ESSENTIALS OF CHEMISTRY. 

Alcohol when concentrated abstracts water from the tissues 
and coagulates their albuminoid constituents ; and is a poison. 
In full doses (always best with food) alcoholic liquors produce a 
sense of warmth in the stomach, general comfort and exhilaration 
followed by incoherence of ideas and impairment of muscular co- 
ordination. 

Taken habitually, in any of its forms, it impairs the mental and 
moral force of its victim, and produces in the various organs, 
especially the liver and kidneys, the degenerative changes charac- 
teristic of " chronic alcoholism." It should never be taken in 
health, but as a medicine it is the most valuable of stimulants. 
In cases of acute poisoning by alcohol, the stomach and bladder 
should be evacuated and the depression (coma) counteracted by 
strong coffee, the cold douche, and other stimulants. 

Triiyl (propyl) alcohol and tetryl (butyl) alcohol need only to 
be mentioned here ; in fact, the only other alcohol of this series 
possessing medical interest is pentyl alcohol. 

Amyl alcohol, pentyl alcohol, C 5 H n HO,'/z^/ oil, This is a 
heavy liquid, soluble in alcohol but not in water, hence incor- 
rectly called an oil. It is produced in fermentation of grain, 
potatoes and other starchy substances, and is the most deleterious 
impurity in common whisky, before it has undergone the refining 
process (rectification). It has a penetrating, disagreeable odor, 
resembling that of mean whisky. Although not fragrant itself, 
its ethers, when dissolved in ethyl alcohol, have the taste and 
odors of various fruits, and are used in the preparation of artificial 
essences. 317 

Sulphur alcohols or mercaptans. It was noted in discussing the 
sulphur group (inorganic) that sulphur had the faculty, in a marked 
degree, of playing the same roles as oxygen and forming analo- 
gous compounds. The sulphur alcohols and ethers are strong 
smelling, irritating bodies, some of which are derived from ani- 

;sl7 To a half drachm of fusel oil in a test-tube add some sodium acetate, 
and a few drops of sulphuric acid. Warm the mixture, and the pentyl (amyl) 
acetate, "essence of pear" will be recognized by its odor. 



PART II. — ORGANIC CHEMISTRY. 1 49 

mals and plants, <?. g., ichthyol and the oils of garlic and mustard. 
Ethyl mercoptcui is ethyl sulphydrate, C 2 H 5 HS, a volatile liquid 
with a powerful odor of garlic — Sulphonal, a white, tasteless 
powder and valuable hypnotic is derived indirectly from it. 

ETHERS. An ether is an oxide of a hydrocarbon radical, for 
example, CH 3 ) s O : here it is noticed that O being bivalent, must 
unite with two molecules of the univalent methyl. These two 
molecules methyl) being alike, (CH 3 ) 2 (di-methyl oxide) is a 
simple ether. Where the two hydrocarbon radicals are unlike, it 
is a mixed ether, as (CH 3 ,C,H 5 ) O (methyl ethyl oxide). Other 
compounds (except hydrates and oxides) of hydrocarbon radicles 
are called compound ethers, as CELXO,, C.H-C1, (C 5 H 11 )C. 2 H : ,0_, 
and CHaCoH-SO^, in which hydrocarbon radicals are made to dis- 
place the hydrogen of nitric, hydrochloric, acetic and sulphuric 
acids respectively. The simple and mixed ethers (oxides; are 
generally made by dehydrating the appropriate alcohols with 
some suhstances very avid of water, as sulphuric acid, and dis- 
tilling the resulting ether. The compound ethers generally, may 
be made by treating the appropriate alcohol with the appropriate 
acid, and distilling off the ether produced in the reaction. 

Ethyl Ether (C 2 H 5 ) 2 0, Diethyl Oxide, Ether, U. S. P. It is 
formed by abstracting H 2 from alcohol, usually by means of 
sulphuric acid, 31 * and hence often given the misnomer, " sulphuric 
ether." 

The reaction is as follows : C 2 H 5 HO rHoSO^CHJiSO^-HoO : 
and then again, QH 5 HSO, - C 2 H 5 HO = (C 2 H 5 ) 2 - H 2 S0 4 . 

To manufacture ether: — Take of ethyl alcohol 1^80 to 90 per 
cent.) five, parts ; of sulphuric acid, 9 parts ; mix, and warm in a 
flask w 7 ith a condenser connection. A thermometer passes 
through a cork and into the liquid. When the temperature has 
reached 284° F., pour slowly more alcohol into the flask through 

318 Into a large test-tube pour alcohol and half as much sulphuric acid; 
warm, and note the odor of ether evolved. Xext adapt a cork with delivery 
tube and slowly distil the ether into a cool test-tube. By adding more alco- 
hol the operation may be repeated again and again. 



150 ESSENTIALS OF CHEMISTRY. 

a second tube, opening through the cork. Keep the temperature 
at 284 . The ethyl-sulphate produced in the beginning reacts 
at 284 upon the alcohol as it enters, forming sulphuric acid 
and ether, which latter distils over with the water formed in the 
reaction. The distillate is a mixture of ether, water and alcohol. 
Shake with soda to get rid of the acid. The lighter layer of ether 
is siphoned off and distilled over lime. The alcohol is removed 
by distilling over sodium, un il hydrogen is no longer evolved. 
The sulphuric acid, being unaltered in the reaction, a small quan- 
tity is capable of converting a large amount of alcohol into ether ; 
in fact, the process might go on indefinitely but for the acid be- 
coming so diluted with the water derived from the alcohol as 
to finally stop the reaction. 

Ether is a colorless, very volatile liquid of a very peculiar odor* 
called ethereal ; and is highly inflammable. It burns easily, and 
its vapor mixed with air or oxygen explodes when ignited. 819 So 
ether should never be used near, especially above, a flame. Ether 
is a valuable solvent, and as it evaporates very rapidly, it is used 
to produce cold. 820 But its chief use in medicine is as an anaes- 
thetic, the vapor being inhaled. Being less liable to paralyze the 
nerve centers, it is safer than chloroform. As a solvent of carbon 
compounds, such as fats, resins, etc., it has a very extended use. 
Commercial ether contains 94 per cent, of ether and is only 
employed as a solvent. 

Test for purity of ether : — Water in ether is detected by a 
turbidity when the ether is shaken with an equal volume of CS 2 . 
Alcohol is detected by shaking with aniline violet which, if 
alcohol is present, causes a coloring of the ether. 

Ethyl chloride C 2 H 5 C1, hydrochloric ether, must not be con- 
founded with the so-called " chloric ether," which is an alcoholic 
solution of chloroform. 

319 Put a drachm of ether in a dish and apply a flame. The vapor, having 
mixed with air, explodes; the rest of the ether burns rapidly. 

320 Set a test-tube of water in a beaker of ether. Blow air briskly through 
the ether; the water will freeze. 



PART II. — ORGANIC CHEMISTRY. 151 

Ethyl bromide C 2 H 5 Br, hydrobromic ether, a valuable anaes- 
thetic, but not much used. It is of great importance to have a 
pure article for internal use, since with an impure one alarming 
after-effects have occurred- Externally, ethyl bromide is useful 
as a spray in neuralgia. 

Ethyl nitrite C 2 H 5 N0 2 , nitrous ether : — If nitric acid is treated 
with copper or starch it loses part of its oxygen, and is converted 
into nitrous acid (HN0 2 ). If alcohol also is added it is 
attacked by the nascent nitrous acid and converted into nitrous 
ether and water, 321 thus : C 2 H 5 HO + HN0 2 = C 2 H 5 N0 2 - H 2 0. 

Nitrous ether is a yellowish liquid of an apple-like odor and 
sweetish taste. It is inflammable and is exceedingly volatile. It 
is used diluted with alcohol, forming the spiritus etheris nitrosi, 
U. S. P., commonly called " sweet spirits of nitre." 

Pentyl nitrite : C 5 H n N0 2 . — Called commonly amy I nitrite. 
Made like ethyl nitrite except that pentyl alcohol (fusel oil) is 
used. 32 * Nitrite of arnyl is a volatile, oily liquid of peculiar odor, 
resembling that of bananas ; and is unstable. It is given by inha- 
lation, especially in angina pectoris, asthma, syncope, tetanus, 
epilepsy, etc. It is the antidote to cocaine. Put up in glass tubes 
and given in doses of two to four drops in brandy, or one to 
three drops by inhalation on the handkerchief. Amyl nitrite is 
so volatile that it is almost impossible to keep it in stoppered 
bottles without loss, especially in warm weather or where it is 
often agitated. 

ALDEHYDES. These constitute the first step in the oxida- 
tion of alcohols to acids, viz. : the removal of hydrogen ; hence 
the name. Since nothing has taken the place of the hydrogen 
removed, they are unsaturated and very prone to change, especially 
to take on oxygen and form acids. The lower aldehydes are 
volatile liquids, having a peculiar odor ; the higher are solids. 

321 Nitrous Ether. Distil a mixture of 1 Cc. of H. 2 S0 4 and 2 Cc. of HN0 3 
and 10 Cc. of alcohol, and note odor of ethyl nitrite m the distillate. 

322 Amy I Acetate. Distil a mixture of 2 Gm. of sodium acetate, 5 Cc. of 
amyl alcohol and 2 Cc. of H 2 S0 4 , and note pear-like odor of amyl acetate. 



152 ESSENTIALS OF CHEMISTRY. 

Methyl Aldehyde (CH 2 0), commonly called formaldehyde, is 
made by the oxidation of methyl alcohol. It is of great practical 
as well as theoretical interest, for besides being a valuable re- 
ducing agent, it is a most powerful antiseptic and preservative, 
especially of the albuminoids, which it attacks, even in vapor, 
with great avidity, making them insoluble, imputrescible and even 
indigestible. A 40 per cent, solution of it is sold under the 
name of "formaline," for preserving and hardening anatomical 
specimens. 

Ethyl Aldehyde, C 2 H 4 0, acetic aldehyde, or simply aldehyde, 
made by the partial oxidation of ethyl alcohol, 323 is a colorless, 
volatile, acid liquid of a pungent, disagreeable odor and taste. It 
is hungry for oxygen and therefore a powerful deoxidizer. 32 * 

Paraldehyde is a modified or polymeric form of aldehyde, its 
formula being C 6 H 12 3 instead of C 2 H 4 0. It is produced by the 
action of small quantities of an acid on ethyl aldehyde, slight 
heat being employed. Paraldehyde is a colorless liquid, and a 
hypnotic, anti-spasmodic stimulant ; and exhibits some diuretic 
properties. It has none of the depressing effects of chloral, nor 
the unpleasant after-effects of morphine, the chief objection to its 
use being its odor and taste. 

Chloral. — If chlorine displaces three atoms of hydrogen in 
ethyl aldehyde, it forms tri-chlor- aldehyde, or chloral (C 2 HC1 3 0), 
a colorless, heavy liquid. With a molecule of water, this forms a 
white crystalline solid, called chloral hydrate, having a pungent 
but an agreeable odor and taste. Warmed with an alkali, it 
decomposes thus : 

Chloral. Sod. Formate Chloroform. 

C 2 HC1 3 + NaHO = NaCH0 2 + CHC1 3 . 
Liebreich thought this reaction would occur in the warm alka- 

323 To a little "bichromate and sulphuric acid mixture " in a test-tube, add a 
little alcohol; or hold a hot glass rod in a beaker containing a little ether. 
The peculiar, pungent odor is that of aldehyde. 

324 To 2 Cc. of aldehyde in a test-tube add a weak solution of ammonio- 
nitrate of silver; the silver salt is deoxidized (reduced) and the metallic 
silver deposits on the sides of the vessel, forming a mirror. 



PART n. — ORGANIC CHEMISTRY. 1 53 

line blood and the sedative action of chloroform be obtained. 
He mistook as to this, but found chloral hydrate a valuable 
hypnotic ; dose, grains 5 to 20. The chloral habit is difficult to 
cure. In overdoses, chloral is a poison, and cases are multiplying 
as its powers become better known. No chemical antidote. 
Evacuate the stomach, give stimulants, and maintain the respira- 
tion and bodily warmth. Chloral hydrate prevents decomposition 
and is therefore a good preservative of animal tissue. 

Croton Chloral, chloral butylicum, is a crystalline body, re- 
sembling chloral. Its action is much feebler than that of chloral. 
The dose is about the same. 

Acetone or di- methyl ketone, C 3 H 6 0. Acetone is a typical mem- 
ber of a class known as ketones, produced in various reactions, but 
especially in destructive distillation. Acetone is a colorless, in- 
flammable liquid of a fragrant, mint-like odor and a sharp, biting 
taste. It is given in doses of from 5 to 15 drops, in water, as an 
alterative and anthelmintic. In acute alcoholism and in certain 
fevers, but more especially in the latter stages of diabetes meilitus, 
acetone appears in the blood (acetonaemia), and is attended with 
lowered temperature, and pulse-rate and general depression, until 
the patient finally dies in coma. 

ORGANIC ACIDS. — These are, in general, the products of the 
complete oxidation of certain alcohols. But many of them, be- 
ing discovered long before this relation to the alcohols was known, 
were given names that refer, not to the alcohols from which they 
are derived, but to some source, quality, use or fancied resem- 
blance. For example, the oxidation-product of ethylic alcohol 
being first found in vinegar (acetum), was, and is still, called acetic 
acid, though ethylic acid would be a more appropriate name. 

Formic Acid occurs in the red ant (formica ritfa — hence its 
name), in stinging- nettle and pine-needles. It is the oxidation 
product of methyl alcohol, but it is best made by distilling a mix- 
ture of concentrated glycerine and dry oxalic acid. It is a color- 
less liquid with a very sour taste. 

Acetic Acid. — HC 2 H 3 2 . — This is the acid of vinegar. Formed 
11 



154 ESSENTIALS OF CHEMISTRY. 

in a great many reactions, but made mainly by the destructive 
distillation of wood, or by the oxidation of ordinary alcohol. If 
wine, cider, or other alcoholic liquor is exposed to the air, a 
fungus {my coder ma aceti) called " mother of vinegar" forms on 
the surface and acts as an oxygen carrier, and the alcohol is con- 
verted into acetic acid, thus : 

C 2 H 5 HO + 2 = HC 2 H 8 2 -(- H 2 0. 

A more rapid process is to pass the alcohol through barrels 
filled with beech shavings covered with " mother of vinegar." 

Acetic acid is a colorless liquid, of a pungent, sour taste and 
smell. When free from water (glacial) it crystallizes at tempera- 
tures below 6o° F. Acetic acid in dilute solution (vinegar) is 
much used for domestic purposes. For medicinal use the crude 
vinegar is purified by distillation, forming acidum aceticum 
dilutum, U. S. P. 

As all the acetates are soluble, their best test is to add a strong 
acid and recognize by its odor, the acetic acid set free. 825 

Butyric (te try lie) Acid occurs in rancid butter, human per- 
spiration, faeces, etc., and pathologically in urine, sputum, etc. 
It is formed by the oxidation of tetryl alcohol, but is best made by 
fermentation of a mixture of sugar, cheese and chalk ; calcium 
butyrate being formed, from which the acid can easily be ob- 
tained on adding sulphuric acid and distilling. It is a colorless 
liquid with the odor of rancid butter. 

Valerianic (pentylic) Acid was first obtained (and named) from 
valerian root, but is now made artificially by oxidizing amyl 
(pentyl) alcohol with sulphuric acid and potassium bichromate/ 26 
It is a thin oily liquid, of a sour taste and disagreeable and per- 
sistent odor of rotten cheese or rats' nests. 

Fat Acids. — Of this series of organic acids, the higher members, 

H25 Test for acetic acid. To a strong solution of an acetate add H 2 S0 4 and 
a little alcohol. Warm and note fragrant odor of ethyl acetate. 

;r26 Valerianic acid. Distil (Fig. 26 [side neck test-tube, etc.]) a mixture 
of 10 Gm. of K 2 Cr 2 7 , 1 Cc. of H 2 S0 4 and 4 Cc. of amyl alcohol. Redistil the 
distillate and note odor, etc., of valerianic acid. 



PART II. — ORGANIC CHEMISTRY. 155 

such as Palmitic ■, Stearic, together with Oleic (which belongs to 
another series), exist in most of the natural fats which are 
compound ethers of various hydrocarbon radicles, especially 
Glyceryl (C 3 H 5 ), with the above-mentioned and other fat-acids. 327 
The natural fats are generally a mixture of several fats. Those 
containing mostly oleate of glyceryl (olein) are liquid ; those 
containing the palmitate or stearate are solid at ordinary 
temperatures. So the cold-blooded animals have liquid fats 
(largely olein) • while warm-blooded, yield mostly the solid 
fats. Many fats partially decompose and oxidize on exposure, 
producing free acids and becoming rancid. Especially is this 
true of butter which, in addition to palmitine, stearine and other 
fats, contains also a certain quantity of cheese-curds, etc. " Oleo- 
margarine," or artificial butter, is made from purified fat (mainly 
palmitine and oleine) by churning it in milk and adding some 
coloring. Drying oils are such as absorb oxygen from the air and 
become resinous, e. g., linseed oil. The fats are fixed (not easily 
volatilized), insoluble in water, soluble in alcohol, ether, etc. 

If a metallic radicle is made to replace the positive (hydrogen) 
radicle of the fat-acid, we obtain, especially with the higher mem- 
bers of the series, a class of substances called "soaps" The 
soaps then are compounds of the metallic radicles with fat-acids. 
The soaps of the alkali-metals (K, Na, NH 4 , etc.) are soluble and 
constitute the true and useful soaps. The soaps formed with the 
other metallic radicals are insoluble, and are usually called 
plasters ; lead plaster 882 is officinal. The "curding" of soluble 
soaps in hard water or water containing salts of metals other than 

327 To 5 Cc. of soap solution add HC1, and note the separation of oily 
globules of fat acids. 

Plasters. Add to successive portions of a soap solution and water : 

328 MgS0 4 and note white precipitate of magnesium soap. 

329 FeS0 4 and note greenish precipitate of ferrous soap. 

330 FeCL and note brown precipitate of ferric soap. 

331 CuS0 4 and note blue precipitate of copper soap. 

331 Pb(C 2 H 3 2 ) 2 and note white precipitate of lead soap. 



i56 



ESSENTIALS OF CHEMISTRY. 



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PART II. — ORGANIC CHEMISTRY. 157 

the alkali-metals is due to the precipitation of insoluble soaps or 
plasters. Soaps are made by the saponification of a fat with a 
caustic alkali. For example : — 

Stearine. Sodium Stearate. Glycerine. 

(C 3 H 5 ) (C 18 H 35 2 ) 3 + 3NaHO == 3 XaC 18 H 35 2 + C 3 H 5 (HO) 3 . 

When soap dissolves in cold water, it probably decomposes into an 
acid salt which makes the soapsuds 3 " 1 and a small quantity of 
free alkali which does the cleaning by dissolving and, to some 
extent, by emulsifying by the fats. 

Methene Series. This series of radicles is bivalent, so that 
their alcohols or acids are diatomic or dibasic. Their alcohols 
are unimportant except, perhaps, ethene alcohol or glycol 
C 2 H 4 (HO) 2 , which though of some chemical interest, has no 
practical application in medicine. Most of the acids of this 
series are Diatomic or Dibasic, 

Oxalic Acil, H 2 C 2 4 , occurs in many plants, mainly as potas- 
sium binoxalate, especially in the sorrel (oxalis) grasses, and in 
the animal economy appearing in the urine, occasionally forming 
calculi of calcium oxalate. It is largely and cheaply made from 
sugar or saw-dust by the oxidizing action of nitric acid or caustic 
alkalies. It is a crystalline solid and closely resembles Epsom 
salts, for which it is sometimes taken by mistake. It is a power- 
ful irritant poison \ and being cheap and largely used for removing 
ink- stains, cleaning copper, etc., poisoning by oxalic acid is by no 
means rare. Its best antidote is chalk or some ether compound 
of calcium, with which it forms a very insoluble compound. Its 
best test is some calcium solution, as chloride, forming a white 
precipitate insoluble in acetic but soluble in hydrochloric acid. 

333 HgCl 2 and note white precipitate of mercuric soap. 

334 Lather. Pour 1 Cc. of soap solution into some soft water in a test- 
tube; shake and note lather. 

33i Lime soap. Next add CaCl 2 and shake; note no lather, but a curd of 
lime soap. 

336 Softening hard water. To a portion of soap solution add XaXO s , and 
then CaCl 2 . Shake and note that CaC0 3 is precipitated and a lather forms. 



158 ESSENTIALS OF CHEMISTRY. 

Lactic Acid, H 2 C 3 H 4 Q3 {lactis, of milk) . — This is the acid of 
sour milk, where it is formed by the fermentation of the sugar of 
milk through the agency of the casein. It is also formed in the 
body by the decomposition of glucose, thus : — 

C 6 H 12 6 — 2H 2 C 3 H 4 3 . 

It is a syrupy liquid, of a very sour taste. 

Succinic Acid, H 2 QH 6 4 , is found in amber (succinum), 
lignite, resins, and in certain animal fluids. When fats are oxidized 
with nitric acid, succinic acid is formed. It is now usually made 
by fermenting malic acid. 

Colorless, odorless prisms, soluble and with an acrid taste ; used 
as an anti-spasmodic and diuretic. 

Malic Acid, H 2 C 4 H 4 5 (malum, an apple\ exists in many sour 
fruits and plants, as apples, cherries and garden rhubarb, but may 
be made artificially from succinic acid. The acid and its salts 
are mostly soluble. 

Tartaric Acid, H 2 C 4 H 4 6 , or H 2 T. — Tartrates exist in the juices 
of many fruits. Grape juice contains much acid tartrate of potas- 
sium (KHT), which, being very insoluble in an alcoholic men- 
struum, is precipitated on the sides of the cask whenever the wine 
ferments. This forms argol, the principal source of cream of tar- 
tar and tartaric acid. Tartaric acid forms colorless crystals, very 
soluble, and of a sharp, agreeable, sour taste. 

It is used in the manufacture of baking powders, in Seidlitz 
powder, and in effervescent drinks. 

Citric Acid is closely related to tartaric acid in its sources pro- 
perties and uses, but it is triatomic or tribasic. It exists in the 
juices of many fruits, especially the lemon. Forms colorless crys- 
tals which are very soluble, and possess a sour taste. Many of 
its salts are used in medicine. 

Methenyl Series. — These are trivalent radicles, and form tria- 
tomic alcohols and acids. The most important member of the 
series is tritenyl, C 3 H 5 , sometimes called propenyl, and more 
commonly glyceryl. Its alcohol is 



PART II. ORGANIC CHEMISTRY. 159 

Glycerine, ox glycerol, C 3 H 5 (HO) 3 . Being made from fats, in 
the manufacture of soaps and candles, it has been called (Scheele, 
1779) "the sweet principle of fats ;" but it has no chemical anal- 
ogy with those ethers, since it is the hydrate of tritenyl, and 
therefore an alcohol. Glycerine is produced in the saponification 
of fats, whereby the fats are broken up into fat acids and glycerol, 
thus : 

Tritenyl Stearate. Sodium Stearate. Glycerol. 

(QH 5 ) (C 18 H 82 2 )s + 3NaHO = 3 NaC 18 H S5 2 + C 3 H 5 (HOj 3 . 

It is a colorless, odorless, sweet, viscid liquid, avid of water, neu- 
tral in reaction, soluble in all proportions in water and in alcohol, 
and a solvent of a great many mineral and organic substances, 
the solutions being called glycerites. On account of its hygro- 
scopic property, it has a wide scope of usefulness in therapeutics 
as a laxative, as a depletant and emollient. 

Tritenyl Nitrate, C 3 H 5 (N0 3 ) 3 , usually called nitroglycerine. 
When glycerine is added drop by drop to a mixture of equal 
volumes of strong nitric and sulphuric acid, until the glycerine 
no longer dissolves, and the liquid is then poured into water, 
nitroglycerine separates as a colorless, heavy, oily-looking sub- 
stance of a peculiar odor and sweet taste. It is a powerful ex- 
plosive, and to prevent its accidental explosion on percussion, it 
is usually mixed with some inert dry powder, as silica, sawdust or 
powdered charcoal, and sold as dynamite or giant powder. Ni- 
troglycerine is much used in medicine (dose, t -J-q gr.) as a pow- 
erful and quick heart stimulant. 

Phenol, phenyl alcohol (hydroxybenzene), C 6 H 5 HO, is gener- 
ally called Carbolic Acid, also phenic, or phenylic, acid ; called 
an acid because it combines with bases to form salts, the carbo- 
lates, or phenates. It belongs in the class of benzene, or aromatic 
alcohols. 

Carbolic acid is formed in a number of reactions, but the com- 
mercial article is obtained exclusively from coal tar. It has a 
strong, disagreeable odor; stains skin and mucous membranes 
white by coagulating their albumin ; and is a corrosive poison. 



l6o ESSENTIALS OF CHEMISTRY. 

Care should be exercised in its local application over large sur- 
faces, even in dilute solution, especially on infants, as poisoning 
may occur by absorption. Injections of carbolic acid are used 
to abdrt boils and carbuncles and also in the treatment of hemor- 
rhoids ; and many fatalities are recorded. Antidote : any soluble 
sulphate as MgS0 4 , then albumin (milk, egg, etc.) in abundance; 
but the most efficient antidote has recently been found to be al- 
cohol. For burns by carbolic acid, glycerine is an excellent 
remedy. 

Sulphocarbolates. Carbolic acid will unite with sulphuric acid 
and form sulphocarbolic acid, C 6 H 5 HS0 4 (phenyl-bisulphate) 
from which are formed the sulphocarbolates, a class of astringent, 
antiseptic salts, much used in medicine. 

Resorcin, C 6 H 4 (HO) 2 , closely related to phenol, but a stronger 
antiseptic and much less poisonous. It is obtained from various 
resins or prepared from benzene. 

Creasoteis a complex mixture obtained from wood-tar ; closely 
allied to carbolic acid in its properties and uses, but may be 
readily distinguished from it by being insoluble in glycerine. 
The best creosote is obtained from beech-wood. It is a colorless, 
or faintly yellow, oily liquid, of a characteristic odor and caustic, 
burning taste. It is at present a popular remedy in pulmonary 
tuberculosis, and has long been used as a sedative and astringent 
in vomiting and diarrhoea, and as a local anaesthetic. Large 
doses are poisonous and the antidote is the same as for carbolic 
acid. 

Guaiacol is a constituent of creasote and is prepared from it 
by fractional distillation. It is a colorless, limpid, oily liquid of 
a characteristic, aromatic odor and taste; extensively used in 
tuberculosis, both pulmonary and intestinal. Guaiacol carbonate 
is better adapted for internal medication, since it is neutral, odorless 
and tasteless, and therefore less irritating. Dose, 2 to 5 grains 
gradually increased to a drachm or more a day. Both guaiacol 
and its carbonate must be given for quite a time in tuberculosis 
before their full effects are obtained. 



PART II. — ORGANIC CHEMISTRY. l6l 

Cresol occurs in several modifications in coal-tar, creasote, 
phenol, etc., and is also made artificially. Though more power- 
fully antiseptic than phenol, it is much less caustic and poisonous. 
Under the trade names of " creolin," "lysol," etc., it is sold for 
domestic use as an antiseptic. 

Salol is phenyl salicylate, C 6 H 5 C 7 H 5 3 , and is an ether. It is 
a white powder, tasteless and insoluble in neutral and acid media, 
but in the presence of the fixed alkalies it breaks up into phenol 
aud a salicylate. 337 When taken, it passes through the stomach 
unchanged, to be decomposed and made available in the bile and 
intestines ; hence used as an intestinal antiseptic and antirheu- 
matic. 

Salophen resembles salol in its physical, chemical and physio- 
logical properties and therapeutic uses. 

Saccharin is a white powder, slightly soluble in water, but at 
least 200 times as sweet as sugar, from which its name is derived. 
It has no chemical analogy to the sugars, but is closely related to 
the phenols. It is used as a substitute for sugar in sweetening, 
but has the disadvantage of disturbing digestion. 

Benzoic Acid. — HC 7 H 5 2 , occurs in benzoin, from which it may 
be sublimed in silky needles slightly soluble in water and of 
a pleasant, balsamic odor/ 38 Much is now made from hippuric 
acid, obtained from the urine of herbivorous animals ; but such 
benzoic acid has a urinous odor. It is made industrially by 
the oxidation of benzene. Is given in doses of 15 grains, as an 
expectorant and as an antiseptic in cystitis, its presence in the 
urine destroying the germs of the alkaline fermentation. This 
and the following acids belong the class of " Aromatic Acids." 

Picric or Carbazotic Acid is trinitro-phenol, C 6 H 2 (N0 2 ) 3 HO, 
u e. 9 phenol in which three molecules of (N0 2 ) have replaced 

337 Salol 7 est, U. S. P. Warm 1 Grn. of salol with liq. potassse enough to 
dissolve it; supersaturate with HC1, and note the precipitation of silky needles 
of salicylic acid, and the odor of phenol. 

338 Benzoic acid. Warm a small lump of benzoin in a test-tube, and note 
sublimate (needles) of benzoic acid. 



1 62 ESSENTIALS OF CHEMISTRY. 

three atoms of hydrogen ; and is made by treating phenol with 
nitric acid. 339 It crystallizes in a yellow powder slightly soluble 
in water and is much used as a dye. If warmed carefully it may 
be sublimed, but if heated suddenly, explodes with violence. It 
behaves as a monobasic acid, and its salts are mostly solid yellow, 
crystalline bodies, some of which are: used in medicine. Vast 
quantities are now used in the manufacture of explosives, as 
" lyddite." It may be recognized by its bitter taste and yellow 
color ; by its coagulating albumin and peptone ; and by a blood- 
red with glucose and a dilute alkali. 

Salicylic Acid (monobasic). — Formerly prepared from salicin, 
but now made by a patented process from carbolic acid. A very 
pure acid is obtained from oil of wintergreen, which consists 
mainly of methyl-salicylate. 340 

Salicylic acid is almost insoluble in cold water ; hence the 
sodium salicylate is usually prescribed, which is also less irritat- 
ing, though not so bland as the corresponding strontium salt. It 
has antiseptic, antipyretic and antirheumatic properties and a 
wide range of usefulness as an application in skin diseases. Test : 
intense violet with a ferric salt. 

Gallic Acid. — When galls are moistened and exposed to the 
action of the atmosphere, the tannin they contain is converted 
into gallic acid. It resembles tannin but does not precipitate 
gelatin. So the gradual conversion of tannin into gallic acid inci- 
dental to leather manufacture is a source of constant loss to the 
tanners, since gallic acid does not tan. 

Pyrogallic Acid sublimes as white, feathery crystals when gallic 
acid is heated. Combined with an alkali, it is used in gas-analysis 

389 pi cr i c acid. Mix 5 Cc. of dilute nitric acid and 2 Cc. of carbolic acid 
and let it cool; boil with 10 Cc. of strong HN0 3 for several minutes, adding 
more HN0 3 , drop by drop, as long as carbolic acid floats on top. Finally 
cast into 25 Cc. of cold water. Note the yellow crystals of picric acid, and 
that when they are dried and dropped into a fire they explode. 

3,0 To 1 Cc. of oil of wintergreen in a test-tube add 5 Cc. of liq. potassae; 
heat until saponification and solution is complete; add HC1 and note the 
mass of silky, white crystals of salicylic acid. 



PART II. — ORGANIC CHEMISTRY. 1 63 

to absorb oxygen ; in photography as a deoxidizer ; externally 
in psoriasis and other skin diseases ; and also as hair-dye. Test : 
a blue with ferrous and a red with ferric solutions. 

The Carbohydrates. 

These substances are closely related to the alcohols, being prob- 
ably aldehydes. They are called " carbohydrates " because they 
contain carbon (six or twelve atoms) and the hydrogen and oxy- 
gen they contain are in the exact proportion to form water. They 
constitute the bulk of all plants. They are divided into three 
groups : Amyloses, C 6 H 10 O 5 ; saccharoses, C 12 H 22 0n, and glucoses, 
C 6 H 12 6 . 

AMYLOSES, C 6 H 10 O 5 . This class includes cellulose, gums, 
starch, dextrin and glycogen. 

Cellulose (cellulin, lignin) forms the cell-walls and tissues of 
plants, and is a distinctive characteristic of the vegetable king- 
dom. Woody fibre, cotton, linen and unsized paper are almost 
pure cellulose. It is insoluble in almost every 341 reagent except 
a solution of cupric oxide in ammonia-water. 3 * 5 Acids precipi- 
tate it as a white mass. 346 Unsized paper dipped into moderately 
strong sulphuric acid, washed and dried, has its fibres aggluti- 
nated, loses its porosity, becomes very tough, and is sold as arti- 
ficial parchment for dialyzers, diplomas, etc. Nitrocellulose or 
" gun-cotton," a powerful explosive, is cotton that has been 
dipped into a mixture of nitric and sulphuric acids, and then 

841 Cellulose. Put bits of filter paper in three test-tubes. 

342 To one add water and boil; no effect. 

848 To the second add KHO solution; the fibres swell and become gelatinous. 

844 To the third add H 2 S0 4 , and note that it turns black. 

345 To the fourth add cupric hydrate solution (made by dissolving Cu(HO) 2 
in aqua ammonise), and note that the paper is dissolved. 

8,6 To the solution add HC1 until the ammonia is neutralized and the deep 
blue color discharged, and note that the cellulose is precipitated as a gelatinous 
mass. 

3i7 Artificial parchment. Immerse a sheet of filter paper in strong H 2 S0 4 
for about 15 seconds; wash thoroughly and dry. Note that the fibres have 
become agglutinated and the paper made stronger. 



164 ESSENTIALS OF CHEMISTRY. 

washed and dried. Mixed with camphor and compressed it is 
celluloid. Its solution in ether, or in a mixture of alcohol and 
ether, is collodion™ The " flexible collodion" contains a little 
turpentine and castor oil ; the " styptic collodion " contains 20 
per cent, of tannin. 

Gums are amorphous, odorless, tasteless, sticky substances ; 
found in many plants ; soluble in water but insoluble in alcohol. 
Some, as gum-arabic, make clear solutions (mucilages) with 
water, while others, like gum-tragacanth, only swell up and form 
a paste. 

Starch (amylum), the most important member of the carbo- 
hydrates, and a valuable food, is found in the roots, 351 stems or 
seeds 349 of all plants. Starch is a white powder consisting of 
granules formed of concentric layers, like an onion. 351 These 
granules all have a similar appearance, yet those from different 
kinds of plants differ enough to enable one by microscopic 
examination to determine the source of any starch (Fig. 39). 
When starch is boiled the granules swell and burst, casting starch 
into the water, appearing to dissolve 353 and forming mucilage of 



348 Collodion. Immerse a pledget of absorbent cotton 15 minutes in a mixt- 
ure of 2 parts of strong H 2 S0 4 and 4 of HN0 3 ; wash thoroughly and dry. 
Note that it burns with a flash, and is soluble in a mixture of ether and alcohol. 

349 Starch. Grind some rice in a mortar, adding water from time to time, 
and strain the milky fluid through a cloth. Separate the starch by subsidence 
and decantation, and finally dry it on filter paper. 

350 Granules. Mount a drop of the milky fluid above mentioned under a 
cover glass on a slide for examination later, when the peculiar structure of the 
granules can be noted. 

351 Starchy tissue. Mount a microtome section of potato, and note, under a 
power of about 3C0 diameters, the granules arranged in cells, and that on ad- 
dition of reagents, such as iodine, the granules are blued and the cell walls 
(cellulose) unaffected. Note also the difference between potato and corn 
starch granules. 

352 Starch Faste. (1) To 1 Gm. dry starch add KHO solution, and note 
that, even in the cold, the granules swell and the milky mixture becomes 
translucent; and 

353 (2) Boil another 1 Gm. of starch with plain water, and note same change. 



PART II. — ORGANIC CHEMISTRY. 



165 



starch, 354 which is used for laundrying and for surgical dressings. 
Starch is a very valuable food. Its best test is iodine, ■*' with 
which it forms a blue, which is somewhat lost on heating and re- 
gained on cooling." 55 

Dextrine is the gum used on postage stamps, and by book- 
binders, and is made from starch in various ways, one of which 

Fig. 39. 




Arrowroot. 



Indian Corn. 



Potato. 



is to heat it to 300 F. for some hours. It is more soluble than 
starch, 360 and this explains the digestibility of crusts and toasted 
bread. It gives no blue with iodine, but a reddish, or wine color/' 61 

304 Dissolve a few drops of starch paste in water, and add a drop of iodine 
solution. Note blue color. 

Divide this blue solution between four test-tubes. 

355 Heat one and note that the blue color disappears, but re-appears on 
cooling, unless heated so strongly that the iodine is drawn ( ff . 

356 To the second add KHO solution, and note the blue is discharged, but 
is restored on adding HC1. 

357 To the third add AgNO a solution, and note that the blue disappears. 

153 To the fourth add HgCL solution, and note again that the blue 
disappears. 

359 Filter some diluted starch paste, and nota that it still responds to the 
tests for starch. 

360 Dextrin. Take about I Gm. of commercial dextrin purchased by the 
demonstrator at the book-binder's. Add it to water, and note that it is 
soluble, sticky and sweet. 

361 Add a drop of this solution to alcohol, and note that it falls as a white 
precipitate, dissolving again on addition of water. To some dextrin solution 
add iodine and note reddish (claret) color. 



1 66 ESSENTIALS OF CHEMISTRY. 

Glycogen (generator of glucose) is a mealy, soluble powder 
found in the animal economy, especially in the liver. Like dex- 
trin it is a derivative of starch, but differs from it in being soluble 
and giving only a wine-color with iodine. It seems to be the 
form in which the carbohydrates are stored up in the liver to be 
used by the system as necessity arises. 

SACCHAROSES, C^H^On. This group includes cane-sugar, 
milk-sugar and maltose. 

Cane-sugar, beet-sugar, sucrose {saccharum U. S. P.) is found 
chiefly in sugar cane and also in beet roots as w r ell as in sugar 
maple. Cane-sugar occurs in the juice of many plants, especially 
in the stalks ; but in the fruit, unless very sweet, the glucoses occur 
oftener. Jt is made commercially as follows : The sap of sugai 
cane or the juice of beet-root is expressed by pressure or extracted 
with warm water and boiled with milk of lime, which saturates the 
acids and precipitates the albuminoid substances. The juice is 
then saturated with carbon dioxide to precipitate the lime, filtered 
through animal charcoal and concentrated in the " Robert's 
machine." By further evaporation in vacuum pans a thick syrup 
is obtained, and on cooling the solid sugar separates. This is raw 
or unrefined sugar, which when purified with a " pure sugar solu- 
tion " in a centrifugal machine becomes refined sugar. It is the 
most soluble, perfectly crystallizable and sweetest of the sugars, 
and the one most used in domestic economy. Its aqueous solu- 
tion is officinal as simple syrup (syrupus simplex). It does not 
respond to the tests for glucose. 362 

Milk-sugar, as its name implies, occurs in milk, though occa- 
sionally elsewhere, as in the liquor amnii of the cow and in certain 
pathological secretions. Prepared by evaporating whey until the 
sugar crystallizes out, and is purified by repeated crystallization. 
It is harder, less soluble and less sweet than cane-sugar and used 

H6i Cane Sugar, (a) Apply Fehling's test to a solution of cane-sugar, and 
note that there is no reduction. 

363 (b) Boil with 5 per cent. H 2 S0 4 or HC1, and, after neutralizing the acid 
with an alkali test for the presence of glucose. 



TART II. — ORGANIC CHEMISTRY. 167 

in the trituration of medicines. 866 As it is less prone to fermenta- 
tion than other sugars, it is preferred in infant feeding. On fer- 
mentation, it forms lactic acid and not alcohol and acetic acid as 
do other sugars. 

Maltose is a sugar formed by the action of malt diastase upon 
starch, as in the " mash " of whiskey and beer ; also produced by 
the action of animal ferments on glycogen. In its power to re- 
duce Fehling's solution, 61 parts of maltose equal ioo of glucose. 

GLUCOSES, C 6 H 12 6 . Of this group we need mention only 
glucose and laevulose. 

Glucose, or grape-sugar, occurs in most sweet fruits, especially 
in the grape, and in honey. It is the sugar of the animal 
economy and the one that appears in the urine in diabetes 
mellitus. It is formed in nature largely by the action of acids and 
ferments 8,T_: ' 71 in conjunction with warmth and moisture on the 
amyloses, saccharoses, glucosides, etc., adding H 2 and breaking 
up their more complex molecules, thus : 

Starch, water, glucose cane-sugar, water, glucose. 

C 6 H ]0 O 6 + H 2 = C 6 H 12 6 ; and C 12 H. 22 O n + H 2 = 2C 6 H ]2 6 . 

* * 64 (c) Heat it dry and note that it melts into a yellowish mass, " barley- 
sugar," and afterwards becomes brown caramel,'" with some glucose. 

365 (d) Add H 2 S0 4 and KHO to successive portions of dry cane sugar and of 
glucose, and note that the acid blackens the cane sugar first, and the alkali 
discolors only the glucose. 

• 66 Lactose. Taste it and dissolve it in w r ater, and note its sweet taste and 
that it responds to Fehling's and other tests for glucose. 

167 Ferment. To successive portions of thin starch paste add (a) a few 
crushed grains of malt. 

368 (b) Some saliva, obtained by chewing paraffine. Towards the end of the 
hour note the sweet taste and test for glucose. 

369 Diastase. To some starch paste in a test-tube add some commercial 
diastase, and set in water not too warm for the finger to be held in it indefi- 
nitely. After a few minutes test for glucose. 

370 Corn Syrup. Add 5 Cc. of H 2 SO + to a beaker of thin starch paste, 
and boil for an hour, or until a drop ceases to be blued by iodine. Add ex- 
cess of marble-dust to neutralize the acid and filter. Note its sweet taste; 
test a portion for glucose; evaporate the rest to a syrup, and allow it to cool. 
Note that it does so promptly and perfectly as cane-sugar. 

371 " Skirt-tail sugar." Let the demonstrator boil some rags with dilute 
(5 per cent.) H 2 S0 4 for several hours, and at the laboratory hour neutralize 
with marble dust, filter and distribute to the students to test for glucose. 



1 68 ESSENTIALS OF CHEMISTRY. 

Vast quantities of glucose are made commercially by boiling 
amyloses, such as starch, 370 or even cellulose 371 with dilute sul- 
phuric acid. Unless the cheap acid used be contaminated with 
lead, arsenic, etc., this artificial glucose (corn-sugar) 370 is as val- 
uable for food as the natural. Glucose is sometimes called dex- 
trose from its turning polarized light to the right. It is a strong 
reducing agent, upon which fact depend most of its tests (for 
these tests see article on urine). 

Laevulose occurs in fruits, etc. in association with glucose, and 
differs from it in turning the ray of polarized light to the left 
(hence its name). It may be obtained pure by separating it from 
the glucose of the invert-sugar made by heating cane-sugar with 
acids. 
Glucosides. 

This group includes a numerous class of substances, mainly of 
vegetable origin, mostly soluble in water and in alcohol ; and 
though differing greatly among themselves, possessing one common 
property, viz. : When acted upon by a ferment or a dilute acid, 
they decompose, producing, among other things, glucose™ Their 
chemical constitution is not thoroughly understood, but probably 
they are ethers of glucose. They generally have marked physio- 
logical action, and are therefore the active principles of the drugs 
in which they occur. Their names generally refer to their origin 
and terminate with re -in" A few of the most important are : 

Amygdalin, found in the bitter almond (amygdala), in the 
leaves of cherry laurel, and in the seeds of peaches, cherries and 
plums, associated with an albuminoid ferment, emulsin or synap- 
tase, which in the presence of heat and moisture decomposes the 
amygdalin into hydrocyanic acid, benzaldehyde and glucose. 

Salicin is the bitter principle in the bark of the willow (sa/ix). 
It has been employed as a substitute and adulterant of quinine, 
from which it may be known by the blood-red it gives with sul- 
phuric acid. 

372 Boil I Gm. of salicin for 15 minutes in 10 Cc. of dilute (5 per cent.) 
H 2 S0 4 , and neutralize with excess of marble dust. Filter and test for glucose. 



PART II. — ORGANIC CHEMISTRY. I 69 

Tannin. This, in several varieties, constitutes the active prin- 
ciple of vegetable astringents. Having an acid reaction and 
combining with various bases, organic and inorganic, it is 
often called tannic acid. With gelatin it forms an insoluble and 
imputrescible compound ; hence used from time immemorial to 
tan leather. It precipitates various metals, especially iron, with 
which it forms a blue-black, much used in inks and dyes, and 
making all vegetable astringents incompatible with solutions con- 
taining iron. 

Myronic Acid exists in black mustard, associated with myrosin, 
an albuminous ferment capable of converting the myronic acid 
into glucose and allyl sulphocyanate, to which latter the mustard 
owes its virtue. Hot water, by coagulating this ferment, renders 
a mustard plaster inert. 

Indican occurs in various plants, the indigofera; also in urine, 
being derived from indol, a weak base produced by the pancreas 
and taken up from the alimentary canal. It is a brownish, bitter, 
syrupy liquid, which, when fermented or treated with dilute acid, 
forms indigo-blue and a kind of glucose. 

Other important glucosides are : Arbutin, cathartic acid, colo- 
cynthin, digitalin, elate rin, gentia?iin, glycyrrhizin (from licorice), 
jalapin, santonin, saponin, solanin, etc. 

Bodies of the Arnmonia Type. 

Taking the molecule of ammonia, NH 3 , as a basis, and by substi- 
tuting for one or more atoms of its hydrogen one or more organic 
radicals or combinations of radicals, we can obtain a large num- 
ber of interesting and important substances • and the number is 
still further increased by polymerism, i. e., the faculty of the 
molecules duplicating themselves, so that one set of compounds 
may be formed on the type of NH 3 and another on that of N 2 H 6> 
and so on. Many of these substances have trade names alluding 
to some use or property, or in abbreviation of their chemical 
names, but their use is almost without excuse, as we have for them 
a very complete and systematic chemical nomenclature, the most 
12 



I70 ESSENTIALS OF CHEMISTRY. 

satisfactory, perhaps, in all chemistry. They bear the names of 
the radicals entering into their own composition, and end in 
"-amine" when those radicals are electro-positive, or in "-amide" 
when electro-negative and containing oxygen. For example : 
Amines — 

Ammonia. Ethylamine. Phenylamine. Trimethylamine. 

• H f C 2 H 5 (ethyl) ( C 6 H 5 (phenyl) f CH 3 (methyl) 



3 

" etc. 



( H f C 2 H 5 (ethyl) f QH 5 (phenyl) ( CH : 

n^h; n^ h ; n^ h; n \ ch, 

(h (h (h (ch; 

Like ammonia, these bodies are alkaline, and combine with acids 
to form salts, appropriating instead of displacing their hydrogen, 
e. g. NH 3 -f- HC1 = NH 4 C1, ammonium chloride or ammonia hy- 
drochloride j in like manner NH a (C 2 H 5 )+HCl=NH a C 2 H B )HC1, 
ethylamine hydrochloride. 
Amides — 



Ammonia 



Acetamide. 



(Amine). 

C 2 H 3 (acetic rad.) 



f H ' f H 

1SN H; INN H 

lH (C 2 I 



Acetanilide. 


Carbamide 


(Phenyl Acetamide). 


(Urea). 


f H 


f H 


C 2 H 3 ; 


NJ H 


(. C 6 H 5 (.phenyl) 


1 >co 




«{» 



Aniline, 873 phenylamine, amidobenzene, made by the action 

!C H 5 °f nascent hydrogen (from HC1 and iron filings) on 
H nitrobenzene. It is a colorless liquid, but its com- 
H pounds, the aniline dyes, are coloring matters of great 
brilliancy. 374 - 376 

373 Aniline from acetanilide. Crush together 1 Gm. each of NaHO and 
acetanilide; warm in a test-tube until they coalesce. Then invert the test- 
tube and continue heating as long as oily globules of aniline run out. Gather 
these in another test-tube and compare with the commercial article. 

Acetanilide. Aniline. Sodium acetate. 

(C,H 8 )NH(C 1 H 8 0)+NaHO=C 6 H ft NH 2 '4-NaC J II s O J . 

374 Rosaniline. To about 2 Gm. of HgCl 2 add 3 drops of aniline, and warm 
until it turns green and then purple. When cool, add a little alcohol and a 
drop or two of HC1. Stir into a beaker of water, and note the purple rosan- 
iline hydrochlorate. 

375 Nitro aniline. Shake a drop of aniline in a test-tube of dilute H 2 S0 4 ; 
mix a few drops of this with a few drops of strong H 2 S0 4 in a porcelain dish, 
and then add a trace of nitric acid, and note dark red color; a delicate test 
for nitric acid. 



PART II. — ORGANIC CHEMISTRY. 171 

When taken or inhaled, aniline is an active poison, but some of 
its salts have found a place in therapeutics, especially the sulphate \ 
one grain doses for chorea and epilepsy. 

Trimethylamine is sometimes confounded with propylamine. 

r qh 3 It is a colorless, volatile alkaloid, with an ammoniacal, 
N -< CH 3 fishy odor. It is found in many animal and vegetable 

( CH 3 substances, but is obtained from pickled herring. The 
hydrochloride is the salt used. Dose, ten to fifteen grains. 

Acetanilide. — This is a derivative of aniline, in which the acetic 

!C 6 H 5 radical, minus O, is made to displace an atom of 
H hydrogen. A crystalline, odorless solid, slightly sol- 

C 2 H 8 u ble in warm water, very soluble in alcohol ; made 
by the action of glacial acetic acid on aniline. In doses of five 
to ten grains, repeated every two or three hours, it is an antipy- 
retic and sedative. It is said not to affect the healthy tempera- 
ture, but to rapidly lower a fever. Its copyright name is " anti- 
febrin." 

Test: a yellow-green color with a green fluorescence when 
heated for some time with an equal weight of zinc chloride. 
Phenacetine. — The formula shows that this substance is closely 

!C 6 H 4 O C 2 H- allied to acetanilide. A white crystalline 
H powder, only slightly soluble in water. In 

C 2 H 3 doses of fifteen grains it causes a fall of 

temperature and a profuse sweat. Its effect is more persistent, 
and perhaps more dangerous than antipyrine, and may produce 
symptoms of aniline poisoning with hsemoglobinuria and jaundice, 
especially if an impure drug be used. Like acetanilide, it is used 
as a substitute for iodoform on painful ulcers, relieving pain and 
promoting healing. 

Antipyrine, C n H 12 N 2 0, a derivative of the artificial alkaloid, 
chinoline, is a white crystalline powder, soluble in water and in 

376 Dissolve a few drops of this anilin in water in two test-tubes. To one 
add solution of chlorinated lime — a purple color is produced; to the other 
add some sulphuric acid and potassium chromate mixture — a blue color 
appears. 



172 ESSENTIALS OF CHEMISTRY. 

alcohol, of a slight tarry taste and odor. With nitrous acid, it forms 
a green precipitate, and is therefore incompatible with spirits of 
nitrous ether. This green color is a test, not only for antipyrin, 
but for the presence as well of nitrous ether, e. g. 9 in any specimen 
of " sweet spirits of nitre." In doses of ten to fifteen grains it is 
a valuable antipyretic and anodyne. The hydrochloride is the 
salt used. 

Proteids. 

The name proteid is given to a numerous and varied class of 
bodies in allusion to their occupying first (protos, first) rank 
among the proximate principles of animal and vegetable tissues. 
They are all highly nitrogenous, and are the only substances cap- 
able of living. They originate only in plant life, and are appropri- 
ated by animals and constitute the major part of the solid portion 
of their tissues and fluids, except the sweat, urine and bile. 
Their ultimate analysis shows about 50 per cent, carbon, 7 per 
cent, hydrogen, 23 per cent, oxygen, 16 per cent, nitrogen and 4 
per cent, sulphur. The empirical formula, C 72 H 112 N 18 S0 2 . 2 , has 
been suggested ; but of their rational formula we know almost 
nothing, except that their molecules must have great weight and 
complexity. They are amorphous, colorless, odorless, colloid 
(uncrystallizable) bodies; and, except peptones, are not osmotic 
— do not dialyze — do not diffuse through animal membranes. 
Some are soluble, others insoluble. Some are rendered insoluble 
by heat or by certain acids, alcohols and metallic salts, these 
serving as tests for the proteids, and the proteids as antidotes to 
them. 

Tests : — (1) They are all precipitated by alcohol, and, in time, 
coagulated. 

(2) Heated with strong nitric acid (xanthoproteic test) they 
turn yellow, owing to the formation of xanthoproteic acid ; and on 
the addition of an alkali, become orange. 

(3) Biuret test : Add a few drops of dilute copper- sulphate 
solution and an excess of KHO ; a violet color appears. 



PART II. ORGANIC CHEMISTRY. 1 73 

(4) Millorrs reagent colors the proteids purple-red on heating. 
This reagent is composed of mercury one part, nitric acid one 
parts, plus two volumes of water. 

Classification of the Proteids : — The physiologists divide the 
proteids into eight classes ; 1, native albumins; 2, globulins; 3. 
derived albumins; 4, fibrins: 5. peptones: 6, albumose ; 7, 
coagulated proteids: 8. lardacein. The latter (lardacein) is an 
amyloid substance found as a pathological infiltration in various 
organs. 

1. Natural Albumins are so called because they occur natur- 
ally in the blood, lymph, chyle, etc., also in the whites of eggs 
and in plants. Natural albumins comprise (a) serum albumin, 

egg albumin, (c) vegetable albumin. 
As a class these albumins are soluble in water ; not coagulated 
by dilute acid unless heated above 167 F. ; coagulated by strong 
acids and by heat. 

rum albumin in solution is a white or pale yellow fluid, 577 
slightly alkaline, and is coagulated by heat and by acids. It is 
not readily coagulated by alcohol or ether. 

Egg albumin (found in solution in the white of ?gg)~~~ is co- 
agulated by ether and very rapidly by alcohol ; otherwise has the 
same characteristics as serum albumin. 

getable albumin (found in nearly all vegetable juices) is co 
agulated by heat and by acids. 

Paralbumin and Jfefalbumin, found in ovarian cysts, belong 
to this class of natural albumins. 

2. Globulins are, as a class, insoluble in pure water; soluble in 
dilute but precipitated by strong sodium chloride solution ; co- 
agulated by heat, and precipitated when carbon dioxide gas is 
passed through them. 

377 1 Maybe easily obtained from blood, 

from which it separates in coagulation, but is sold dried for calico printing 
and sugar refining. 

of Egg Albumin. Through a small hole in the end of an 
egg pour out the white, leaving the yolk in the shell. Break up the white 
with a glass rod and strain through wet muslin. 



174 ESSENTIALS OF CHEMISTRY. 

Globulins comprise (a) para- or serum-globulin, found in blood- 
serum and in lymph ; (b) fibrinogen found in blood-plasma, 
lymph, chyle, etc.; (c) myosin, 319 found in muscle, and, by its 
coagulation, responsible for the condition known as rigor mortis ; 
(d) crystalling found in the crystalline lens ; (e) vifellin, 381 found 
in the yolk of egg. 

3. Derived albumins (albuminates) are as a class insoluble in 
water and in dilute sodium chloride solution, but soluble in dilute 
acids and alkalies; not coagulated by heat. Derived albumins 
comprise : (a) acid albumin™ formed by treating natural albumin 
with dilute acid (HC1) for a considerable while; (b) syntonin,™ 5 
made by digesting myosin with weak HC1, and precipitating with 
an alkali, when it appears as a pasty, whitish mass ; (c) alkali 
albumin, made by treating natural albumin with an alkali ; 384 is 
slightly soluble in water and in sodium chloride solution, differ- 
ing therefore from acid albumin; (d) casein, made by diluting 
milk with four volumes of water and acidulating with acetic acid 
until the milk contains about T \- per cent. ; (e) Legumin (vege- 

379 Preparation of Myosin. Chopped lean beef is soaked in water, and the 
water expressed through a cloth, and the process repeated until all albumin is 
removed. The residue is then soaked in 10 per cent, salt solution, which when 
expressed is found to contain the myosin. 

380 Preparation of Crystallin {globulin). Grind up with 10 Cc. of water in 
a mortar, the crystalline lens of an ox, and filter off the water, which removes 
the albumin. Rub up the residue with 10 Cc. of 10 per cent, salt solution 
which dissolves the crystallin. 

38i Preparation of Vitelin. Wash the yolk free from the white, and shake 
it with ether in a test-tube to remove the fats. Pour off all the ether possible, 
and let the rest evaporate. Impure vitellin remains. Water does not dissolve 
it, though salt water makes a milky solution. 

382 Preparation of Acid Albumin. Stir 20 drops of glacial acetic acid with 
the white of one egg until it forms a gelatinous mass of acid albumin. This 
is then dissolved in a beaker of warm water for use. 

383 Preparation of Syntonin. Chopped beef is repeatedly soaked in water, 
and the water expressed to remove the serum albumin. The residue is then 
digested in a 0.2 per cent, solution of HC1, and the solution expressed con- 
tains the syntonin or muscle acid-albumin. 

384 Preparation of Alkali Albumin. With the white of one egg, stir 3 Cc. 
of KHO solution. Dissolve the gelatinous mass in a beaker of water to use 
as a solution of alkali albumin. 



PART II. ORGANIC CHEMISTRY. 1 75 

table casein), found in the seeds of peas and beans, also in 
almonds, and reacting like milk casein. 

4. Fibrins are, as a class, insoluble in water, difficultly soluble 
in strong acids and alkalies, whereby they are changed to de- 
rived albumins; coagulated by heat. Fibrins comprise (a) 
blood fibrin; produced by the action of fibrin ferment upon the* 
fibrinogen and fibrinoplastin of blood, lymph, chyle, etc., whereby 
a clot is formed ; insoluble in water, alcohol or ether, but slowly 
soluble in dilute acid; (b) Glutin (vegetable fibrin) existing in 
vegetables and probably a mixture of several proteids ; insoluble 
in water, alcohol or ether. 

5. Peptones, as a class, are soluble in water, acids, alkalies and 
sodium chloride solution. They are precipitated by alcohol, 
tannic acid, bichloride and potassium-mercuric chloride. With 
C11SO4 solution (a few gtt.) and KHO in excess, peptones give 
a red color. Pepsin of the gastric juice and the trypsin of pan- 
creatic juice, in the process of digestion, act upon proteids to con- 
vert them into peptones, which are diffusible (osmotic). 

6. Albumoses are soluble in dilute sodium chloride solutions 
and in water, give a red color, as do the peptones, with CuS0 4 
and an excess of KHO. Albumoses are intermediate between 
acid-albumin and peptone. 

7. Coagulated proteids are as a class, insoluble in water, sod- 
ium chloride, dilute or alkali. They are the result of the action 
of heat, acids, alcohols, etc., on true albumins or globulins. 

8. Lardacein, as stated above, is found as an amyloid infiltra- 
tion in various organs and tissues in persons long suffering from 
wasting disease. In composition, it is a proteid, but is not di- 
gested by pepsin and HC1 and with iodine it strikes a red ; or a 
blue, if previously treated with sulphuric acid. 

Alkaloids. 

Alkaloids (alkali-like) are organic alkalies, a class of bodies of 
alkaline reaction and capable of neutralizing acids and forming 
with them distinct and crystallizable salts. They are undoubtedly 
amines or amides, u e., ammonia in which one or more atoms of 



176 ESSENTIALS OF CHEMISTRY. 

hydrogen in the molecule, NH 3 , are replaced by one or more or- 
ganic radicles or combinations of organic radicles, but the mole- 
cules seem to be far more complex than those artificial alkaloids. 
Of late years chemists have made a number of amines, some of 
them similar, if not identical with certain natural alkaloids ; and 
the time seems not far distant when our most costly and complex 
alkaloids will be made artificially ; in fact, all that seems to pre- 
vent it now is not knowing the exact constitution of such complex 
molecules. In plants alkaloids are not found free, but combined 
with some vegetable acid forming a salt. Their salts (except 
tannates) are usually soluble and intensely bitter; the free alka- 
loids, being much less soluble, are much less bitter. Those alka- 
loids (as conine and nicotine) that contain no oxygen are liquid ; 
but the great majority of them are white powders. 

Alkaloids are so seldom prescribed in the free state that when 
the simple name of an alkaloid is written in a prescription the 
druggist puts up its most common salt. The names of alkaloids 
end in "-ine" and are derived from the names of the plants in 
which they exist or from some characteristic property. 

The intense effect alkaloids exert on the animal organism makes 
them generally the active principles of the drugs in which they 
are found. But the active principle of a drug is not always an 
alkaloid. The alkaloids include the majority of our most potent 
remedies and powerful poisons. Tannin is a common antidote, 
but most important is the prompt evacuation of the stomach and 
the intelligent use of physiological antagonists. 

The alkaloids, even those of medical interest, are so numerous 
that to give each separate consideration would cover a great por- 
tion of the materia medica. We can mention but a few of the 
most important. See Table, page 178. 

Ptomaines are putrefactive alkaloids, — The word "ptomaine" 
was first used by an Italian, Francesco Selmi, who discovered in 
decomposing organic matter certain basic, alkaloidal bodies. He 
recognized their resemblance to the vegetable alkaloids, and called 
them in contradistinction ptomaines (n-ra^a, a corpse) or cadaver 



PART n, — ORGANIC CHEMISTRY. I 77 

alkaloids. Later study has taught us that the various bacteria act 
upon organic matter, and with the requisite amount of heat and 
moisture, cause its decomposition with the production of pto- 
maines. As a rule, bacteria will cause these putrefactive changes 
only in dead animal or dead vegetable matter, but in pathological 
states it is possible for germs to flourish and multiply in the living 1 " 
organism, causing the same putrefaction, and hence the same pro- 
duction of ptomaines. The different bacteria produce different 
ptomaines ; thus the typhoid bacillus produces typhotoxine, the 
tetanus bacillus produces tetanine. It is generally accepted to- 
day tnat the symptoms of infectious diseases and specific fevers 
are due solely to the poisons produced by bacterial growth in the 
living organism : and since analogous conditions and symptoms 
may be brought about by the administration of the ptomaine ob- 
tained from any given bacteria, this view is evidently correct. 

The poisoning that frequently results from eating spoiled meat, 
fish, etc., is due to ptomaines. The symptoms of poisoning by 
ptomaines resemble those by the vegetable alkaloids, except that 
there is usually more gastro-intestinal irritation. The resemblance 
of the physiological effects and chemical tests to those of such 
alkaloids as strychnine, morphine, conine, nicotine, atropine and 
veratrine, is apt to, and doubtless has often led to the escape of 
the guilty and the condemnation of the innocent. Among the 
poisonous ptomaines may be mentioned, besides typhotoxine and 
tetanine, tyrotoxicon. a very poisonous alkaloid, discovered and 
described by Vaughan. It is found in spoiled milk and in ice 
cream and cheese made from it. Tyrotoxicon poisoning is char- 
acterized by a chill, with nausea and vomiting, epigastric pains, 
griping, purging and perhaps collapse and death. Spasmatoxine is 
obtained from the bacillus of tetanus, and like tetanine, which is 
obtained from the same bacillus, produces decided convulsions. 

Other poisonous ptomaines are, isoamylamine, a very poison- 
ous, and rapidly fatal alkaloid, found in decomposing yeast and 
in cod- liver oil ; tetanotoxine, susotoxine, neurine, coline and mus- 
carine (obtained from poisonous mushroom), are decidedly 
poisonous ptomaines. 



178 ESSENTIALS OF CHEMISTRY. 

Among the non-poisonous ptomaines may be mentioned : Neu- 
ridine, methylamine, trimethylamine, ethylamine and diethylamine, 
pyocyanine (from bacillus pyocyaneus), mydine, etc. 

Putrescine and cadaverine are only slightly poisonous. Since 
some ptomaines are not poisonous and others are decidedly 
toxic, it has been considered best to invent the term " toxines " 
for the poisonous ones. 

Leucomaines are a class of alkaloidal substances produced in 
the living body as a result of fermentative changes or of the 
processes of retrograde metamorphosis, as, for example, urea. 
They are eliminated in the various excreta. If retained, as in 
uraemia, or produced in abnormal quantity, as in dyspepsia, they 
act deleteriously on the nerve-centers, causing vertigo, lassitude, 
drowsiness, vomiting, purging and coma. Some elevate, while 
others lower the temperature. Of the more important leucomaines 
may be mentioned : Kreatine, kreatinine, xanthine, hypoxanthine, 
paraxanthine, heteroxanthine, pseudoxanthine, spermine, sala- 
mandarine, etc. Most of the leucomaines are non-poisonous ; 
some few are decidedly toxic. 

Bacterial Proteids. — Very little is known of bacterial proteids 
since they quickly decompose. The bacterial proteid poison of 
diphtheria, of tetanus, of cholera and of typhoid have been iso- 
lated. These proteids, or toxalbumins, as they are sometimes 
called, are formed by the action of bacteria on albuminous 
material ; and their effect upon the animal organism, when 
administered internally or hypodermatically, is to produce 
symptoms identical with those of the bacterial infection. 

Antitoxine. — A few words must be said about antitoxines : It 
has been found that when an animal has recovered from certain 
infectious diseases, there is present in the serum of that animal's 
blood something which confers partial or complete immunity to 
the animal against further attacks from the same disease ; and 
this serum, when injected into other animals exhibits the same 
protective power. The composition of this substance is un- 
known, but on account of its antitoxic effects it has been called 
antitoxine. We have already a diphtheria antitoxine, a tetanus 



PART II. ORGANIC CHEMISTRY. 



179 



antitoxine, a streptococcus antitoxine, etc. Clinical results have 
shown conclusively that a new field of therapy is open here to 
the physician. Let us hope that this " serum-therapy of Behring " 
will do as much in other infectious diseases as has already been 
accomplished in variola by Jenner's discovery of vaccine. 

TABLE OF COMMON ALKALOIDS. 



Name. 


Formula 


Source 


Remarks. 






r 


Crystalline ; morphia gives a blue 


Morphine 
Codeine 
Narcotine 
Narceine 


C 17 H 19 N0 3 
C, s H 21 N0 3 
C,,H., 3 N0 7 


"] Opium 
1 « 

\ « • 
j 


with FeCl.^, and a red with 
HNO s . These alkaloids and 
several others exist in opium in 
combination with meconic acid, 
which gives with Fe.,Cl 6 a red 








color not discharged by HgCl.,. 


Apomorphine 


C 17 H 17 N0 2 


Morphine 


Made by heating morphine with 
HC1; a systemic emetic. 


Quinine 


C 20 H 2i N 2 O 2 


1 




Quinidine 


« 


f 


All crystalline except quinoidine, 


Quinicine 


t( 


1 Cinchona J 
hark 


which is a resinous mass. To 


Quinoidine 


it 


test for quinine, add chlorine 


Cinchonine 


C 19 H 22 N 2 


water, shake, and then add aq. 


Cinchonidine 


a 


I 


ammonia; a green color. 


Cinchonicine 


a 


J 




Strychnine 


C 21 H,,N,0 2 


Nux vomica 


Crystals; gives a purple with 
H,S0 4 K,Cr.,0 7 or MnO.,. 


Brucine 


CjgH^NA 


u 


Crystals; gives a red with HN0 3 . 


Aconitine 


c; h;.no 7 


Aconite 


) 


Colchicine 


C 17 H 19 N0 5 


Colchicum 


V Crystals; very poisonous. 


Veratrine 


C 32 H 52 N 2 8 


Veratrum 


J 


Atropine 


C 17 H.„NO, 


Belladonna 


) 


Hyoscyamine 


c 15 h.;no 3 


Hyoscyamus 


y Crystals; used to dilate the 


Homatropine 


C 16 H 22 N0 3 


Atropine 


) pupils. 


Hyoscine 


C 1T H 2l N0 4 


Hyoscyamus 


Sedative and hypnotic; crys- 
tals. 
Crystals; soluble in water. 


Caffeine 


C 6 H I0 N + O 2 


Coffee 


Theine 


it 


Tea 


Crystals; soluble in water. 


Theobromine 


C 7 H 8 N,0 2 


Chocolate 


Stimulant, crystals. 


Cocaine 




Coca leaves 


Crystals; soluble in water; 








weakly basic ; local anaesthetic. 


Physostigmine 


C 15 H. 21 N,0 2 


Physostigma 


Crystals; contracts the pupils. 


(Eserine) 




(Calabar bean) 




Pilocarpine 


C n H 16 N 2 2 


Jaborandi 


Crystals; a powerful diaphoretic. 


Urea 


CH 4 N 2 


Urine 


Crystals; may be made artifi- 
cially by heating NH 4 CNO. 


Nicotine 


o 5 h 7 n 


Tobacco 


Liquid; powerful poison. 


Conine 


C 8 H 15 N 


Hemlock 


(t a a 



PART III.— CLINICAL CHEMISTRY. 



THE URINE. 



The urine is a fluid secreted continuously by the kidneys, and 
is the chief means by which the nitrogenous waste of the body is 
discharged; 385 

A specimen, to be representative, should be a portion of the 
whole twenty-four hours urine, for considerable variation in cora- 

* 85 The rationale of its secretion is one of transudation, osmosis, and elabo- 
ration. Owing to the resistance encountered by the blood in its exit through 
the efferent vessel, there is an increase of blood pressure in the Malpighian 
tuft and a transudation of the water of the blood with some dissolved salts 
into the capsule. From loss of water the blood is very much thickened when 
it reaches the second capillary system surrounding the convoluted tubes, which 
contain the thin, watery transudation from the Malpighian bodies. Here are 
the essential elements of a complete osmometer — an animal membrane, com- 
posed of the thin wall of the capillary and the delicate basement membrane 
of the tube, with a dense fluid (the thickened blood) on one side and a thin 
saline solution on the other. An interchange now takes place of the water 
from the tube to the blood, and of the products of retrograde metamorphosis 
(urea, etc.), and salts from the blood to the tubes, concentrating the fluid in 
the latter, making it urine, while the albuminous constituents of the blood, not 
being osmotic, are retained. An elaborative function has long been attrib- 
uted to the epithelial cells lining the convoluted tubes, for it was observed 
that whenever the tubes lost their epithelial lining (as in some forms of 
Bright's disease), urea, etc., failed to be eliminated. This function of the 
cells may be demonstrated by injection into the veins of a rabbit a solution of 
sulph-indigotate of sodium. If the animal be killed within a few minutes, 
none of the coloring matter will be found in the capsules, while the cells 
lining the tubes will be stained blue. If, however, an hour be allowed to 
elapse, even the cells will be found colorless and the coloring matter will be 
seen only in the urine. Our conclusion drawn from this is that the production 
of urine is chiefly an elaborating or secreting process, regulated in its fluidity 
by the glomerular system; that the water and some of its salts are secreted 
by the glomeruli, the peculiar anatomical construction of which permits a 
varying degree of activity corresponding chiefly with the varying degree of 
blood pressure and blood fluidity; while in the main, the solid excretory pro- 
ducts of the urine are elimated by the epithelium of the renal tubules, through 
their vital, selective or secretory power, as in all other glandular structures of 
similar anatomical construction. 

(180) 




PART III. CLINICAL CHEMISTRY. l8l 

position and properties may occur during the day. Especially is 
this true of traces of albumin and sugar. When this is impractic- 
able, that passed before breakfast is generally preferable, because 
farthest from a meal. When significant variations during the day 
are suspected, several specimens may be taken 
33^ at different hours. For microscopical exami- 
nation, a few ounces of the urine in a stop- 
pered vial, or covered conical glass, Fig. 44, 
are set aside for several hours until the sedi- 
ment, having settled to the bottom, can be 
examined. A much more improved and satis- 
factory method is by the use of the centrifuge, 
as thereby the precipitate can be obtained at 
once from fresh urine. 

Physical Properties. 

Normal urine is a transparent, aqueous fluid, of a pale yellow 
color, characteristic odor, faint acid reaction, and of a specific 
gravity of 10 20 when passed in the average quantity of about 1500 
Cc. {48 fl. ounces) in the twenty four hours. This description is 
to be taken with much allowance, for very wide variations occur 
even in health. With these variations the student must become 
thoroughly familiar before he is capable of interpreting a speci- 
men. 

Quantity. — hi health, the average adult secretes about 1500 Cc. 
(48 fl. ounces) a day, most in the afternoon and least at night; 
but the quantity may vary widely (from 500 Cc. to 5000 Cc.) de- 
pending upon, (a) the quantity of liquids ingested, and (b) its 
vicarious elimination by the skin, lungs and bowels. 

In disease, it may be increased (polyuria) or diminished (olig- 
uria) or even suppressed (anuria). 

Polyuria occurs in (a) diabetes mellitus or insipidus; (b) con- 
tracted and amyloid kidney; (c) pyelitis; (d) cardiac hyper- 
trophy; (e) after the crisis of acute diseases; (/) during rapid 
absorption of exudates and transudates ; (g) in nervous excite- 



152 ESSENTIALS OF CHEMISTRY. 

ment, as epileptic and hysterical attacks or even fright and an- 
xiety ; (h) after administration of diuretics. 

Oliguria occurs in {a) fevers and inflammatory affections; (b) 
acute nephritis ; (V) excessive elimination of water by other chan- 
nels, as in sweating, diarrhoea, etc. ; (d) conditions of lowered 
arterial tension as in heart failure, exhaustion, shock, etc. 

Anuria or suppression of urine differs from oliguria only in 
degree and should not be confounded with retention, in which 
case the urine is secreted, but retained in the bladder. 

Transparency. — Normal urine is not always transparent, nor is 
transparent urine always normal. Some degree of opacity may 
be due to (a) Mucus, which, with entangled epithelial cells, may 
be observed as a slight cloud in many specimens of healthy urine, 
especially of females because of the larger area of mucous surface 
in that sex. This faint cloud may be seen floating at any depth 
and is unaffected by most chemicals except acetic acid, which 
may slightly increase the opacity by coagulating the mucin. The 
mucus is usually removed by filtration ; (b) Urates (of Na, K, 
Ca, and Mg), which often form a precipitate in the urine, especi- 
ally when allowed to cool, as in standing over night in a cold 
room. The test for this sediment is heat, which quickly dissipates 
it. (Y) Earthy phosphates (of Ca and Mg), which may give an 
opacity to normal urine if it is alkaline or even ceases to be acid. 
The test for this sediment is that it promptly clears up, on the 
addition of a few drops of any acid, while heat would only in- 
crease it. (d) Fungi (bacteria, penicillia, sarcinae, etc.), especi- 
ally in decomposing urine. 

A urine may be abnormally opaque or cloudy from the above- 
mentioned causes, or from the presence of blood, pus, epithelia, 
tube casts, fat globules/ 86 etc. When due to blood, pus or organ- 
ized detrita, the opacity is increased by heat or acids because of 



38(i In chyluria the urine is mixed with chyle, the fat being in a state of 
emulsion, and is milky, and if alkaline, is even viscid. I have seen it only a 
few times in this country, but it is common in the tropics, and is due to the 
presence of the filaris sanguinis hominis. 



PART III. CLINICAL CHEMISTRY. 1 83 

the precipitation of albumin which is always present in liquor san- 
guinis and liquor puris, and is usually associated with tube- casts, 
etc. 

Fluidity. — Healthy urine is neYer otherwise than an aqueous 
fluid, flowing and dripping with ease ; but in certain diseased 
conditions, abnormal quantities of mucus, or the presence of pus 
or fat, especially if the urine be allowed to decompose and be- 
come very alkaline, may make it more or less viscid. 

Color. — Healthy urine is of a pale yellow, or amber color, the 
depth of which varies greatly according to the quantity of water 
present and the consequent degree of concentration or dilution. 
Aside from abnormal degrees of the above, pathological variations 
in color may be the result of (a) a diminution of the normal color- 
ing matters, as in anaemia, diabetes and certain forms of kidney 
disease; (5) an increase of the normal coloring matters, as in 
fever and other diseases destructive of blood and tissue ; (c) by 
the presence of abnormal substances, as biliary and blood color- 
ing matters. 

(a 7 ) Moreover, the urine may be colored after the administra- 
tion of certain drugs, as senna, santonin, rhubarb, carbolic acid, 
prickly pear, etc. 

Odor — Urine has a charactetistic odor, the strength of which 
depends mainly on its concentration. When freshly passed, it 
has also an aromatic fragrance, due to certain volatile ethers. 
The more concentrated the urine, the stronger the odor because 
of the larger quantity of urea it contains. 

Diabetic urine exhales a sweetish and fruity smell, owing to the 
presence of acetone. In certain forms of dyspepsia and of liver 
trouble, the odor of the urine is almost pathognomonic. Medi- 
cines and certain articles of food often impart a peculiar odor, as 
turpentine the odor of violets, asparagus and cauliflower a rank, 
disgusting smell ■ also cubebs, copaiba, sandalwood-oil, garlic, 
tolu and salol, impart their characteristic odors. 

Reactio?i. — Normally the urine of the whole twenty-four hours 
will average an acid reaction ; but great variations occur during 



1 84 



ESSENTIALS OF CHEMISTRY. 



the day. Before meals it will have a high degree of acidity, but 
after meals becomes nearly neutral or even alkaline. This is due 
to the ingestion of food, which is largely alkaline, and to the ab- 
straction of acidulous principles from the blood to form acid gas- 
tric juice. It has also been observed that urine passed on rising in 
the morning is especially acid. This is probably owing to the fact 
that during sleep less carbonic acid is exhaled from the lungs, and 
less perpiration (acid) given off by the skin. 

The urine is especially acid whenever the albuminoid tissues are 
being rapidly oxidized as in fever, diabetes, carcinoma, etc. It is 
especially alkaline after the ingestion of alkaline salts or of neutral 
salts of vegetable acids and alkali metals, the acidulous radicals 
of which are oxidized in the blood, so that the salts appear in the 
urine as carbonates. This explains the alkaline urine of vegeta- 
rians and herbiverous animals. 



Fig. 45. 




Sediment from a urine in " acid fermentation." (a) Fungus; (b) amorphous sodium urate; 
(c) uric acid; (d) calcium oxalate. 

The reaction of urine is important to the physician, as it may 
favor or prevent irritations of the kidneys and bladder or the for- 
mation of sediments and concretions. The acidity of urine is 



PART III. CLINICAL CHEMISTRY. 



185 



due, not to free acid, but to acid sodium phosphate (NaH 2 P0 4 ) 
occurring in consequence of carbonic, uric and hippuric acids, 
seizing on to a portion of the sodium of the phosphate (Na 3 P0 4 ). 
The degree of acidity is best measured by a decinormal alkaline 
solution (see Acidimetry, page 96). 

An acid fermentation, attended by a decomposition of mucus 
and coloring matters and a production of acetic and lactic 
acids, sometimes occurs in urine that has stood for some at a mod- 
erate temperature (Fig. 45). After a while, more quickly in 
warm weather, the alkaline fermentation begins, caused by the 
development of the micrococcus ureae (Pasteur). The urea is con- 
verted into ammonium carbonate, thus: (NH 2 ) 2 CO^ 2H 2 = 
(NH 4 ) 2 C0 3 . This gives the urine an ammoniacal odor and alka- 
line reaction, and it becomes opaque from the precipitation of 
urate of ammonium (Fig. 46), and the earthy phosphates and the 








Sediment from a urine in the " alkaline fermentation." {a) Ammonium urate; (b) ammo- 
nio-magnesium phosphate; (c) bacterium ureae. 



development of bacteria. Pus and blood or vessels tainted with 
urine previously fermented greatly hasten this change. The re- 
action is recognized by litmus paper. If acid, the blue litmus is 
13 



i86 



ESSENTIALS OF CHEMISTRY. 



turned red ; if alkaline, the red litmus is turned blue ; if neutral 
there is no change in either. If alkalinity be due to ammonia 
(volatile alkali) the blued paper gets red again on drying. 

Specific Gravity. — Though the average specific gravity is 1020, 
it exhibits, even in health, great variations, the extremes being 
1002 after copious use of water and diuretics, and 1040 after ab- 
stinence from fluid and the elimination of water through other 
means, as profuse perspiration or copious diarrhoea. The amount 
of solids varying but little in health, fluctuations in specific gravity 
are due mainly to variations in the amount of water ; so, as long 
as the inverse proportions between specific gravity and volume of 
urine is preserved, variations need cause no alarm. Marked de- 
partures, however, from this inverse ratio are of the gravest 
import. A specific gravity too small for the volume of urine indi- 
cates renal defect and heralds uraemia ; a specific gravity too 
high would indicate glycosuria or excessive tissue waste, as in 
fevers. 

Fig. 47. 




Fig. 48. 



30 



40 
Diagram. 



Specific gravity is usually measured by an instrument called a 
hydrometer or urinometer (Fig. 47), which is a hollow, glass float, 
weighted with mercury and having a long, graduated neck. The 
graduation begins above at 1000, because the heavier the urine 



PART III. CLINICAL CHEMISTRY. 187 

the less deeply will the instrument sink and the further ne neck 
will protrude from the surface. It is well to test a new urino- 
meter by immersing it in water at 6o c F. (15.5 C), when it 
should sink to o, or 1000, on the scale. Urinometers are usually 
provided with a cylinder, or jar, as shown in the figure, but a large 
test-tube will answer. This is about three-fourths filled ; the 
urinometer is then introduced, and when still, the specific gravity 
is read off. The cylinder or test-tube should not be too narrow, 
lest the urinometer be attracted to and catch against the sides, 
and not rise as high or sink as low as it should. One of the 
best urinometers on the market is Squibb's, in which the jar is 
sharply fluted inward near the middle and the bulb of the float 
is made oval so as to present little surface for contact. A ther- 
mometer is also provided. For every seven degrees of tem- 
perature above the normal (6o° F. or 15 .5° C.) one degree of 
specific gravity should be added to the reading. The fluid being 
attracted up around the stem, the reading should be made not 
along the line c d y as in the diagram (Fig. 48) suggested by Dr. 
Leffmann, of Philadelphia, but along a b, which represents the 
true level of the liquid. 

To approximate the amount of solids in any urine; {a) the 
last two figures of the specific gravity represent the number 
of grains of solids to the fluid ounce ; (b) doubling the last two 
figures of the specific gravity, gives the per cent. Thus, if the 
urine be of the specific gravity 1020, and the daily volume fifty 
ounces : — (a) 20 (grains per fluid ounce), multiplied by fifty 
(ounces daily volume) gives 1000 grains of solids per diem; (b) 
.020 X 2 = .040 or 4 per cent, which multiplied by fifty (ounces 
daily volume) gives 2 ounces of solids per diem. 

The solids of the urine may be accurately determined by tak- 
ing a certain volume of urine, e. g., 100 Cc. and evaporating it in 
a previously weighed porcelain dish over a water-bath, until it no 
longer loses weight, when it is finally weighed and the weight of 
the dish subtracted. 



155 ESSENTIALS OF CHEMISTRY. 

Chemical Constituents. 

The average composition of a thousand parts of urine is about 
as follows : 

f Water 950.00 

Urea 26.20 

Organic J Creatine an ^ kreatinine, xanthine and allantoine .80 

I Urates of sodium and potassium 1.45 

I Hippurates of sodium and potassium 70 

L Mucus and coloring matters .35 

p Phosphates of sodium and potassium 3.75 

Ino anic j Phosphates of calcium and magnesium 90 

j Chlorides of sodium and potassium I2 «55 

^ Sulphates of sodium and potassium 3.30 

1000.00 

Pathologically there may be present also albumin, glucose, 
blood, bile, etc., besides various other sediments. 

»{! 

Urea, J:>CO, or carbamide, is the most constant and 

abundant organic constituent of the urine, and being the main 
nitrogenous excretion, is the index of nitrogenous waste, whether 
of food or of tissue. Its average amount is about one ounce per 
diem. Urea may be obtained by extracting it from the urine, or 
artificially by heating cyanate of ammonium, with which it is iso- 
meric [(NH 4 CNO= (NH 2 ) 2 CO).] 

It crystallizes in colorless prisms, very soluble in water, and 
behaves like an alkaloid, combining readily with nitric and oxalic 
acids to form salts. Both of these salts may, by adding nitric or 
oxalic acid, be precipitated from concentrated urine as colorless, 
rhombic or hexagonal plates. 387 (Fig. 49.) 

It was formerly believed that the kidneys were the seat of the 

387 Test for urea. On a glass slide place a drop or two of suspected fluid, 
add a drop of nitric acid, warm over a spirit lamp; if urea is present the 
characteristic rhombic or hexagonal crystals of nitrate of urea can be seen 
with a microscope. 



PART III. — CLINICAL CHEMISTRY. 



189 



formation of urea, but this has been proved an error, from the 
fact that after complete extirpation of the kidneys, urea continues 
to be formed. It is believed now that the liver, and perhaps also 
the spleen, and the lymphatic and secretive glands, take active part 
in the formation of urea. Its formation is markedly diminished 
in degenerative changes in the liver, as in acute yellow atrophy of 
the liver. Urea is abundantly formed in diabetes ; the activity of 
the hepatic cells being much increased, sugar and urea are 
formed in great quantities, and after being passed into the blood 
are excreted by the kidneys. In suppression of the urine, due to 
diseases of the kidney, the formation of urea continues and is 
accumulated in the system, giving rise to uraemia. A meat diet 
increases the quantity of urea and a vegetable diet diminishes it. 

Fig. 49. 




(a) Prisms of urea; (5) hexagonal plates; and (c) rhombic plates of nitrate of urea. 



In the course of many diseases it is important to estimate the 
amount of urea excreted day by day. A rough estimate may be 
based on the specific gravity. For, since urea is the largest solid 
ingredient in urine, it follows that if sugar be absent, albumin in 



T90 



ESSENTIALS OF CHEMISTRY. 



small amount or removed, and the quantity of chlorides normal, 
variations in specific gravity must be due mainly to variations in 
the amount of urea. 

The exact methods most generally employed consist in decom- 
posing the urine into nitrogen and carbon dioxide, by means ot 
sodium hypochlorite or hypobromite, and measuring either the 
volume of gas evolved or the specific gravity lost by the decom- 
position. 

Davy's Hypochlorite Method. — A graduated tube closed at one 
end is one-third filled with mercury. A measured quantity of the 
urine (a drachm or half drachm, according to capacity of tube) 
is then added, and the tube is next filled to the brim with the 



Fig. 50. 



Fig. 51. 




ni w 




Doremus'. 



Davy's. 

hypochlorite solution (liq. sod. chloratse, U. S. P.). Closing the 
opening with the thumb, the tube is inverted over a strong solu- 
tion of common salt in a dish (Fig. 50). The mercury runs out 
and the salt water rises to take its place, while the urine and soda 
mixture, being lighter, remain in the upper part of the tube. 
Here the gas from the decomposing urea collects. The decom- 
position is complete in three or four hours, when the amount of 



PART III. CLINICAL CHEMISTRY. 191 

the gas may be read off by the graduations upon the tube, every 
cubic inch representing .64 grain (or 1 cubic centimetre repre- 
senting 2.5 milligrams) of urea. This method is now but little 
used. 

Doremus* Hypobromite Method. — The sodium hypobromite is 
prepared by adding 1 cubic centimetre of bromine to 10 cubic 
centimetres of sodium hydrate solution (100 grammes to 250 
cubic centimetres of water, or 6 ounces to one pint) and diluting 
with 10 cubic centimetres of water. Tilt the ureometer (Fig. 
51), and pour the hypobromite into the long arm, completely 
filling it. Draw the urine to be tested into the pipette to the 
graduation. Pass the pipette into the ureometer as far as the 
bend, and compress the nipple slowly. The urine will arise 
through the hypobromite, and the gas evolved will collect in the 
upper part of the tube. The ureometer is graduated to indicate 
either the number of milligrams of urea to the cubic centimetre 
of urine or the number of grains to the fluid ounce. This method 
is so quick and simple that it is the one generally employed by 
physicians. 

Squibb 's Apparatus is similar to the foregoing, but has the ad- 
vantage of employing the easily obtained liquor sodae chloratae 
U. S. P. 

Fowler's Method. — The specific gravity of the urine is carefully 
determined as well as that of the liq. sodae chloratae (U. S. P.) to 
be used. One volume of the urine is mixed with exactly seven 
volumes of the liq. sod. chlor. and set aside for two hours, or 
until effervescence ceases. The specific gravity is again taken. 
As the reaction begins immediately on mixing the fluids, the spe- 
cific gravity of the mixture must be determined by calculation. 
This is done by adding to the specific gravity of the urine seven 
times that of the liq. sod. chlor. and dividing the sum by eight. 
Each degree of difference in specific gravity of the mixture before 
and after the decomposition represents three and a half grains 
of urea to the fluid ounce of the day's urine, or seven grams to 
the liter. 



192 ESSENTIALS OF CHEMISTRY. 

Example : 

Quantity of urine in twenty-four hours 46 oz. 

Sp. gr. of the urine 1020 

Sp. gr. sod. chloratse 1042 

^/..jx . . ,1042 X 7 + I02 ° \ , 

(Calculated) sp. gr. mixture ( — -' — — ) 1039.2+ 

o 

(Actual) sp. gr. mixture after reaction 1036.2 

1939.2— 1036.2 = 3 ; 3 X 3^ = 103^ grs. of urea to the ounce 
of urine ; 10*^ X 46 = 483 grs. of urea passed in the twenty-four 
hours. 

Kreatine and Kreatinine, occur in normal urine, but so spar- 
ingly as to be of little practical importance. They are closely 
allied chemically and physiologically with urea ; appearing in acid 
urine as kreatinine, C 4 H 7 N 3 0, and in alkaline as kreatine, 
C 4 H 9 N 8 2 , differing in composition only by the molecule, H 2 0. 

Xanthine and Allantoin are substances closely allied to uric 
acid ; occur in normal urine so sparingly as to be of little practical 
importance, and need only be mentioned in this connection. 

Uric Acid (H 2 C 5 H 2 N 4 3 ), formerly called lithic acid, is 
found in the urine of carnivora : in that of herbivora it is largely 
replaced by an analogous substance — hippuric acid. Gout is 
characterized by an increased production of uric acid, and the 
so-called " chalk-stone " deposit in the joints during that disease 
is sodium urate. Free uric acid is so very insoluble that when- 
ever it exists in urine it is always a precipitate. It appears as 
minute reddish grains, which under the microscope are seen to 
be modifications of rhombic crystals, always stained with the 
coloring matter of the urine. They often deviate widely from the 
typical rhomb, as shown in Figs. 52 and 53, but an experienced 
eye will readily recognize them. Normally, uric acid as soon as 
formed unites with the alkaline bases to form urates. These are 
very soluble in warm water, but more sparingly so in cold. 
Therefore a urine, though clear when freshly passed and warm, 
may exhibit a copious precipitate upon becoming cold, as on a 
winter night This precipitate is easily recognized by its dis- 



PART III. — CLINICAL CHEMISTRY. 



193 



solving upon warming. Urates of sodium and magnesium gener- 
ally appear under under the microscope as amorphous powders 
in moss-like aggregations, but occasionally as bundles of small 



Fig. 52. 



Fig. 53. 







mm 





Uric acid. 



Uric acid. 



needles, as shown in Fig. 54. The urate of ammonium, a result 
of the alkaline fermentation, occurs as opaque, brown spherules, 
smooth or with spiculae like a thorn apple (Fig. 46). 



Fig. 54. 




Urates in bundles of small needles. Calcium oxalate. 



Uric acid, being dibasic, can form both normal and acid salts. 
If much acid is present in a urine, the normal urates give up one 



194 ESSENTIALS OF CHEMISTRY. 

atom of their metallic base and become acid urates. These are 
less soluble than the normal, and often precipitate when the 
urine is very acid [see Fig. 45 (b)~\ or when an acid is added, as 
in the nitric acid test for albumin. 

The murexid test for uric acid and the urates is one of great 
beauty. Place some of the sediment in a porcelain dish, add a 
drop or two of nitric acid, and carefully evaporate almost to dry- 
ness. Add a few drops of ammonia; or, better still (Earp) in- 
vert the dish over another in which a dry ammonium salt is vola- 
tilized. If uric acid is present, a beautiful purple color will 
appear. 

Coloring Matters. — Our unsatisfactory knowledge of these 
substances and their clinical significance is to be regretted, since 
some of them possess an importance next to albumin and sugar. 
The existence of at least two distinct substances has been 
demonstrated : 

1. Urobilin {Urohcematin) , a brown, resinous substance, de- 
rived from the coloring matter of the bile, and hence indirectly 
from the coloring matter of the blood. 

It occurs in normal urine, and in larger quantity in the urine 
of patients suffering from any disease which causes disintegration 
of the blood copuscles. 

1. Uro-indican (uroxanthin) a substance closely related to, 
but not identical with, the glucoside indican, and, like that sub- 
stance, capable of conversion into indigo-blue. It seems to be 
derived from the indol formed in the fermentation of albuminous 
matters, especially in the alimentary canal. It is therefore in- 
creased in obstructive troubles and in certain diseases character- 
ized by decomposition of albuminoids or impairment and per- 
version of general nutrition; so that its presence is not patho- 
gnomonic of any one disease. 

To roughly estimate the coloring matters, put the urine in a 
beaker and render it strongly acid with nitric or hydrochloric 
acid. Let it stand six hours for the color to be developed. Then 
note the depth of color by transmitted light. 



PART III. CLINICAL CHEMTSTRY. 1 95 

A striking method, especially for indican, is that of Jaffe. 
Take equal quantities of the urine and fuming HC1, and then add 
drop by drop with constant stirring, a fresh sat. sol. of calcium 
hypochlorite until the maximum of blue is produced. This is 
then shaken with chloroform, which seizes the freshly-formed 
indigo and soon settles to the bottom as a blue liquid, the depth 
of color indicating the amount of indican in the urine. 

Phosphates. — The phosphates are derived mainly from the 
food, but to some extent also from oxidation of phosphorized 
tissues : 

1. Earthy Phosphates (Ca and Mg). — Being soluble only in 
acid solutions, the earthy phosphates are precipitated when the 
urine is made or becomes alkaline. Furthermore, being less sol- 
uble in warm than in cold urine, heat often precipitates them, as 
in the heat test for albumin. Deposits of calcium and magnesium 
phosphates are generally amorphous, and may be distinguished 
from the amorphous urates, (a) by absence of color and by not 
gathering in mossy forms j (a) • by a drop of acetic acid added 
to the sediment on a glass slide under the microscope — phos- 
phates dissolve, while urates gradually lose their base and assume 
the characteristic forms of uric acid. In ammoniacal urine 
(alkaline fermentation) the ammonio-magnesium phosphate 
(MgNH + P0 4 ), the so-called triple phosphate is formed and de- 
posited in large prismatic, coffin-lid crystals; sometimes also, in 
ragged stellate or aborescent crystals, resembling those of snow. 
(Fig. 55.) In cases of cystitis this may occur within the bladder ; 
hence other calculi often have one or more white layers of the 
mixed phosphate. 

2. Alkaline Phosphates. — These constitute the greater portion 
of the phosphates, and are made up mainly of acid sodium phos- 
phate, with traces of potassium phosphate. Being very soluble, 
they never form a precipitate. 

Tests : (a) The earthy phosphates may be detected by the 
addition of any alkali e. g. liquor potassae, and gently warming. 
The normal amount produces only a whitish cloud, or opales- 
cence. 



196 



ESSENTIALS OF CHEMISTRY. 



(b) To detect and estimate the alkaline phosphates the pre- 
ceding should be filtered and the filtrate treated with magnesia 
mixture. U. S. P. 388 

(V) The " total phosphates " are best detected and estimated 




Ammonio-magnesium Phosphate. 

by precipitation with the magnesia mixture. If the precipitate 
is thick and creamy, the phosphates are increased ; if milky, 
they are normal ; and if translucent, they are diminished. 

(a 7 ) Centrifugal Test. — Fill graduated tube to 10 Cc. mark 
with fresh urine ; add 5 Cc. of magnesia mixture, mix and then 
rotate for three minutes at the usual speed of one turn of the 
handle to the second. Normally the sediment should occupy ten 
per cent. 

Pathologically the phosphates are decreased in gout and most 
inflammatory diseases, especially in nephritis. This is a very 
valuable and almost constant symptom. They are increased in 
wasting diseases of the osseous and nervous systems and markedly 
so in the so-called " phosphatic diabetes," a disease attended 
by the various symptoms of denutrition. 

Chlorides. — These, normally about 15 Gm. a day, consist 



388 Magnesia Mixture, U. S. P. Magnes. Sulph., 10 Gm.; Ammon. Chlor- 
ide, 20 Gm.; Water, 80 Cc; Ammonia water, 42 Cc. 



PART III. CLINICAL CHEMISTRY. 197 

almost entirely of sodium chloride, the quantity depending mainly 
on what is taken in with the food. However, in many fevers, 
especially in pneumonia, the chlorides may be diminished in the 
urine or may even disappear from it, much being eliminated by 
sputa. Their reappearance in the urine is often the earliest indi- 
cation of convalescence. Hence their detection and estimation 
are important. 

Silver-Nitrate Test, — First add a few drops of nitric acid to 
prevent the precipitation of the phosphates. Then, on adding 
silver-nitrate solution (i to 500), the chlorides will fail as a white 
precipitate of silver chloride. If the precipitate is in curdy 
masses, the chlorides are not diminished ; if only a milkiness is 
produced, they are greatly diminished ; and if no cloudiness, they 
are entirely absent. 

Centrifugal Test. — To 10 Cc. of the urine in the graduated tube 
add a few drops of nitric acid and fill to the 15 Cc. mark with a 
solution of silver nitrate (1 to 500), mix and then rotate as in the 
preceding. The amount, if normal, should occupy about 15 per 
cent. 

Sulphates. — These consist mainly of sodium sulphate, with a 
little of the potassium salt. They are derived principally from 
the food and in small quantity from oxidation of albuminoid sul- 
phurized tissues, especially in fevers. 

Tests. — {a) Barium Test. — First add a few drops of nitric or 
hydrochloric acid to hold the phosphate in solution ; then add 
barium chloride test-solution U. S. P. (12.2 per cent.) until pre- 
cipitation is complete. If the precipitate is creamy, the sulphates 
are increased ; if milky, normal , and if only opalescent, dimin- 
ished. 

(b) Centrifugal Test. — To 10 Cc. of urine add a few drops of 
nitric acid and fill up to the 15 Cc. mark with the barium chloride 
test-solution ; after rotation the volume of the precipitate is nor- 
mally one per cent. 



198 ESSENTIALS OF CHEMISTRY. 

Abnormal Urine. 

Urine may be abnormal from excess or diminution of the fore- 
going normal constituents or from the presence of various sub- 
stances that are never found in healthy urine. Of these, the most 
important are the proteids, namely, albumin, globulin, albumose 
and peptone. 

Albumin. — By this is generally meant serum albumin which, it 
not being osmotic, appears in the urine only in pathological con- 
ditions and in certain functional disturbances, due to abnormal 
difTusibility of the blood's albumin or to excessive blood pressure 
in the kidneys, or oftenest, to lesions in the renal tissues them- 
selves. 

Heat Test. — A test-tube is one -third filled with the suspected 
urine and held in the flame of a spirit-lamp, or over the chimney 
of an ordinary lamp, until it boils. If an opacity occurs, it must 
be either atbumin or earthy phosphates. If earthy phosphates, it 
clears up on addition of nitric acid, but if albumin, it is slightly 
increased. 

Nitric Acid Test. — This consists in under-laying the urine with 
nitric acid. Take a test-tube one-fourth full, and, holding it 
aslant, gently pour in an equal volume of the acid, allowing it to 
trickle down the inside of the tube and pass beneath the urine. 
Or, the acid may be put in first and the urine added afterward. 

Howe's method of applying this test is : Pour about 5 Cc. of 
the urine into a test-tube and warm it to about ioo° F. Through 
a funnel pipette, reaching to the bottom of the test-tube, add an 
equal volume of nitric acid. If albumin is present, there will ap- 
pear at the junction of the two liquids a narrow white band, best 
seen in a strong light, against a black back-ground. 

An opacity at the junction of the two liquids is either albumin 
or urates. Ifurates, it clears up on heating, but if albumin, it is 
permanent. Either the heat or nitric acid test, singly, is unsatis- 
factory, but both performed together are conclusive. However, 
the following sources of error should be borne in mind : (a) if 
the urine is very alkaline and the quantity of albumin small, heat 



PART III. CLINICAL CHEMISTRY. 1 99 

will cause no opacity ; (b) If only a drop or two of nitric acid be 
added, the acid may hold a small quantity of albumin in solution ; 
(V) urea may be precipitated from a concentrated urine by nitric 
acid, but heat dissolves it; (d) decomposed urines, containing, 
as they do, ammonium carbonate, effervesce on addition of an 
acid; (<?) often after taking turpentine, copaiba, etc., nitric acid 
precipitates the resin in yellowish flakes, re-dissolved on addition 
of alcohol. 

Other Tests. — Among them may be mentioned (a) saturated 
solution of picric acid; (b) potassio-mercuric iodide solution, 
made as follows : mercuric chloride, 1.35 Gm. ; potassium iodide, 
3.32 Gm. ; acetic acid 20 Cc. ; water, 80 Cc. ; the chloride and 
iodide are dissolved separately in water, and then mixed and the 
acetic acid added afterward, (c) A mixture of equal parts of 
the saturated solutions of sodium tungstate arid of citric acid, (d) 
The potassium ferrocyanide test-solution U. S. P. is mixed with 
the urine, and a few drops of acetic acid added, (e) Acidulated 
brine test : a saturated solution of common salt to which 5 per 
cent, of hydrochloric acid is added. Tablets of these chemicals 
or strips of filter paper steeped in them and dried are sometimes 
carried for use at the bedside. 

Quantitative Estimatio7i. — During the progress of a disease it 
is often important to estimate the quantity of albumin. The 
exact method, by drying and weighing the precipitated albumin, is 
too tedious for the busy practitioner. 

The easiest approximative method is to precipitate the albumin 
by heat, set it aside for twelve hours or until next visit, and 
then note the proportion of volume occupied by the precipitate, 
e. g., one-fourth, one-eighth, a trace, etc. 

Esbach's Albuminometer (Fig. 56), is a graduated test-tube. 
Fill it to U with the urine, and to R with the reagent, which 
is composed of 10 grams of picric acid, 20 grams of citric acid, 
and water sufficient to make a litre. Gently mix the liquids and 
set aside for twenty-four hours to allow the precipitate to subside, 
the depth of which by the scale indicates the number of parts 
per thousand or grams of albumin in a litre. 



200 ESSENTIALS OF CHEMISTRY. 

Centrifugal Test — Purdy's method is to add to 10 Cc. of the 
urine in the graduated tube, 3.5 Cc. of the potassium ferro- 
cyanide solution and 1.5 Cc. of acetic acid. After mix- 
ing and the usual rotation, all the albumin is precipi- FlG# s6, 
tated, and each .1 Cc. represents 1 per cent, bulk measure 
of albumin. 

Globulin is sometimes associated with albumin in urine, 
being held in solution by the chlorides. When these be- 
come very much diluted, as on allowing a few drops of the 
urine to fall into a glass of water, the globulin is precipi- 
tated as a white cloun, which dissolves on addition of 
acetic acid. 

Albumose, which is an intermediate product in the di- 
gestion of albumin into peptone, occurs in some cases of 
albuminuria and in osteomalacia. It may be detected by 
acidifying the urine with acetic acid, adding a saturated 
solution of common salt, boiling and filtering to remove 
the albumin and globulin. Albumose will separate as a white 
cloud as the filtrate cools, dissolving again on heating and reap- 
pearing on cooling. 

Peptone is never found in normal urine, but sometimes occurs 
with albumin or independent of it. It differs from albumin and 
albumose in not being coagulated by heat, nitric acid or many 
other substances that coagulate albumin. It is precipitated, how- 
ever, by tannin and phospho-tungstic acid. 389 

To detect peptone, the albumin should be first removed, e.g., by 
acetic acid and potassium ferrocyanide and filtering. It is well 
also to remove the urinary pigments by acetate of lead and filter- 
ing. If phospho-tungstic acid is added to this filtrate a white 
precipitate is formed if peptone be present. 

A simpler but less reliable test is to float the urine over Fehl- 

889 Phospho-tungstic acid is made by treating a hot solution of sodium 
tungstate with phosphoric acid till decidedly acid, and then strongly acidify- 
ing with acetic acid. Filter after standing several hours. 






PART III. — CLINICAL CHEMISTRY. 201 

ing's solution and look for the rose-red zone (biuret reaction) 
indicative of peptone. 

Clinically peptonuria indicates the disintegration and absorp- 
tion of pus corpuscles somewhere in the body and so is a valuable 
symptom in the differentiation between purulent and nonpurulent 
diseases, e. g., between hydro- and pyothorax or between tuber- 
cular and cerebro-spinal meningitis, the latter being purulent and 
attended with peptonuria. 

Mucin. — In moderate quantity, mucin is a normal constituent of 
urine ; but may be abnormally increased in irritation of the 
genito-urinary mucous membrane. It is closely related chem- 
ically to albumin ; but not coagulated by heat or strong 
mineral acids ; but is precipitated by alcohol and organic acids. 
Mucin is one of the most frequent sources of error in searching 
for small quantities of albumin. It is easily detected by its form- 
ing, on standing, a sediment slightly opalescent from entangled 
epithelia and floating near the bottom of the urine. It may be 
detected also by floating the urine over acetic acid and noting 
the slight coagulation in the zone of contact. 

Sugar {Glucose). It has been proved (Dr. Pavy, 1879) that 
healthy urine may contain traces of glucose ; but that quantities, 
appreciable by the ordinary tests and of chemical significance, 
constitute glycosuria, which is the most prominent and some- 
times the only symptom of diabetes mellitus — a serious patho- 
logical condition, associated with disturbance of the glycogenic 
function of the liver. 

A temporary glycosuria may occur after the administration of 
anaesthetics and other drugs, and in certain nerve and brain 
lesions, especially those involving the floor of the fourth ventricle. 
High specific gravity in a urine, pale and copious, suggests sugar. 
Before testing, albumin, if present, should be removed by boiling 
and filtration. 

Fermentation Test. — Two vials, one for comparison, the other 
for fermentation, are partly filled with the urine. Into one is put 
a bit of baker's yeast about the size of a pea. Both vials are 
14 



202 ESSENTIALS OF CHEMISTRY. 

loosely plugged with some pervious material, as cotton, and set 
aside where they will keep warm (6o° or 70 F. ) until next day 
or next visit. If sugar is present, fermentation will occur in the 
vial treated with yeast, and C0 2 bubbles up and passes off 
through the cotton plug ; and on taking the specific gravity of 
each, there will be a difference, owing to the loss of sugar in the 
vial fermented. 

Alkali Test. — Boil the urine with liquor potassae or sodae, and 
if glucose is present, it will be oxidized and form a molasses-like 
coloration, the depth of which indicates the quantity of sugar 
present. On adding nitric acid a molasses-like odor is developed 
and the coloration is discharged. 

Alkali- Copper Test. — This depends on the power glucose has 
of reducing the cupric to the cuprous oxide. There are several 
methods of performing this test : — 

(1) Trommels. A drop or two of a weak (about 1 to 30) 
solution of cupric sulphate is added to an inch of urine in a test- 
tube, and then an equal bulk of liquor potassae or of liquor 
sodae. Immediately there falls in addition to the earthy phos- 
phates, a bluish precipitate. If sugar is present, this precipitate 
dissolves on agitation, forming a blue solution, which, on boiling, 
deposits a yellow, orange or red precipitate of cuprous oxide. 
(See page 120.) 

(2) Fehling's. This differs from Trommer's in that tartaric 
acid or some tartrate is added to dissolve the blue precipitate. 
Furthermore, the ingredients are in definite proportion, so as to 
make the solution available for quantitative analysis. Below are 
given the two formulae in general use, one in the French and the 
other in the English measures : — 

Fehling's Solution. Pavy's Solution. 

Cupric sulphate 34*64 grams. 320 grains. 

Potassium tartrate 173.20 grams. 640 grains. 

Caustic potash 80.00 grams. 1280 grains. 

Water, enough to make 1 liter. 20 ounces. 

(3) Haines* differs from Fehling's in that glycerine is used 



PART III. CLINICAL CHEMISTRY. 203 

instead of the tartrate, and that it does not spoil. Dissolve 
34.64 gm. of cupric sulphate in 200 Cc. of water and add 175 Cc. 
of glycerine. Dissolve 130 gm. of caustic potash in 500 Cc. of 
water. Mix the two solutions and dilute to one liter. 

Alkali- Bismuth Test. — ( 1) To some urine in a test tube add a 
pinch of bismuth subnitrate and then an equal volume of liquor 
potassae. Boil about two minutes. If sugar be present, the bis- 
muth will be reduced and deposited as a black metallic deposit 
on the sides and bottom of the tube. (2) A bismuth test solu- 
tion, corresponding to Fehiing's, is made by warming a scruple 
each of bismuth subnitrate and tartaric acid in two ounces of 
water, and adding liquor potassae until a clear solution is obtained. 
This boiled with a urine containing glucose gives the black bis- 
muth precipitate. 

The elements of the foregoing tests put up in pellets or tablets, 
while more convenient, are less reliable and spoil sooner than the 
solutions. 

Picric Acid Test, — This is an extremely delicate test for glu- 
cose, and depends on the fact that glucose in the presence of a 
strong alkali will reduce yellow picric acid solution into blood red 
picramic acid. It has the practical advantage of being as good a 
test for albumin. To the suspected urine add an equal volume 
of a saturated solution of picric acid. A cloudy precipitate in- 
dicates albumin. Next add a few drops of liquor potassae and 
warm gently. A deep red color indicates sugar, though a lighter 
coloration may occur in urine free from glucose. 

Indigo- Carmine Test. — To the urine add a solution of indigo- 
carmine rendered alkaline by sodium carbonate. Boil, and if 
sugar is present the blue mixture changes to violet-red and yel- 
low. On agitation, oxygen is absorbed from the air, and the 
above changes of color are reversed. 

Phenyl-hydrazin Test. — A very certain though somewhat tedious 
test is made by mixing in a dish 25 Cc. of suspected urine, 1 gm. 
of phenyl-hydrazine hydrochlorate, .75 gm. of sodium acetate and, 
unless the urine is already sufficiently diluted, 10 Cc. of water 



204 



ESSENTIALS OF CHEMISTRY. 



Heat the dish on a water-bath for an hour : when removed and 
allowed to cool there will appear, if sugar is present, a yellowish 
deposit of phenyl-glucosazon, which under the lens is seen to con- 
sist of bundles of needle-like crystals radiating from a common 
center. 

Quantitative. — (i) Fermentation. Each degree of specific 
gravity lost in fermenting represents one grain of sugar to the 
ounce of the twenty-four hours' urine. 

(2) Fehling's. Two hundred minims of the solution is decolor- 
ized by one grain of sugar. Two hundred minims (grains) of the 
test solution are measured off into a small flask, diluted with 
twice its bulk of water, and gently boiled (Fig. 57). A gradu- 

Fig. 57. 




ated burette (also shown in figure) is then filled to zero with the 
urine. To the boiling test solution, the urine is added drop by 
drop till the blue color is discharged. By the graduations on the 
burette the quantity of urine added is easily read. As that repre- 
sents one grain of sugar, the amount of sugar in the entire urine 
is easily calculated. 

3. Alkali Test. A light yellow indicates one per cent. ; dark 
amber, two per cent. ; sherry wine, three per cent. ; dark Jamaica 
rum, five per cent. ; and dark, almost opaque, ten per cent. 



PART III. CLINICAL CHEMISTRY. 205 

Acetone is found in the urine in cases where there is great de- 
composition of tissue albumin, as in high fevers, diabetes mellitus, 
carcinoma (in the stages of breaking down), inanition, mania and 
intestinal auto-intoxication. It is said to be a constituent of nor- 
mal urine, but only as a trace. It often precedes a more danger- 
ous symptom, namely, diaceturia. It is acetone that gives 
diabetic urine its fruit-like odor. 

Lichen's Test. — Add to urine a solution of sodium hydrate in 
excess and then a few drops of a solution of iodine and potassium 
iodide. If acetone is present there occurs a precipitate of iodo- 
form with its characteristic odor. 

Diacetic Acid. — Since it never occurs in normal urine, its pres- 
sure must always be regarded as a dangerous symptom. It has 
been observed that it is always of more significance when found 
in adults than in children. In diabetes millitus it is preceded by 
acetonuria and is generally followed by coma (diacetic coma 
usually known as diabetic coma) and by death. 

In children there sometimes occurs an idiopathic diaceturia 
or an auto-intoxication, attended by malaise, thickly coated 
tongue, generally constipation, slight or no fever, vomiting, 
dyspnoea, jactitation, coma and death. In other cases, however, 
the symptoms last two or three days and then recovery takes 
place. Diaceturia may also occur during the high temperature 
of some of the acute diseases, as typhoid, pneumonia, miliary 
tubercolosis and others. 

Test. — Solution of ferric chloride with urine containing diacetic 
acid gives a red color, but caution must be used since certain 
drugs, as the cinchona salts, acetic, formic, carbolic and salicylic 
acids, may cause the same reaction in the urine. 

Calcium Oxalate occurs in extremely small amounts in normal 
urine, but more abundantly in the so-called oxalic diathesis and 
in certain forms of dyspepsia, or after eating rhubarb or other 
things containing it. If persistently present, it may form a (mul- 
berry) calculus. It occurs in both acid and alkaline urine, and 
always as a light, delicate precipitate, which under high powers is 



2O0 



ESSENTIALS OF CHEMISTRY. 



seen to consist of small, brilliant, octahedral crystals, but some- 
times dumb-bells. (Fig. 54). In certain aspects the smaller 
octahedra appear as squares crossed by two bright diagonal lines. 

Calcium Carbonate is a very rare deposit in human urine, 
but abundant in that of cattle. It occurs in small spherules 
(Fig. 58) sometimes coalescing; acetic acid dissolves it with 
effervescence. 

Hippuric Acid {Horse-uric Acid) largely replaces uric acid in 
the urine of herbivorous animals, and, to some extent, in that of 
man, especially after a vegetable diet. It occurs in pointed, four- 
sided prisms and acicular crystals, insoluble in acetic acid but 
soluble in alcohol. (Fig. 58.) 

Fig. 58. 




Carbonate of Calcium. Hippuric Acid. 

Bile. — In certain conditions, especially those attended with 
jaundice, the urine contains bile coloring matters and usually 
smaller quantities of the bile-acids. Such urine is yellowish- 
brown, forms a yellow froth on agitation, and white paper or cloth * 
N wet with it is stained yellow. 

Tests for Bile Coloring Matters™ — Underlay the urine with 



390 Bilirubin oxidizes so easily that icteric urine often gives only the green 
coloration, or, if kept long, fails to respond at all. Hence, if fresh icteric urine 
cannot be obtained and bile urine must be prepared for demonstration, fresh 
bile from a recently killed animal, and not the inspissated, must be used. 



PART III. CLINICAL CHEMISTRY. 



207 



(a) yellow nitric acid (that containing nitrous acid) f 9] or (b) a 
mixture of nitric and sulphuric acids ; or (c) tincture of iodine. 
If bile is present, there is observed at the junction of the liquids a 
play of colors in which green is prominent and characteristic. If 
the acid and urine are placed adjacen on a white plate, the colors 
are more plainly visible. Another method of performing these tests 
is to shake the urine with chloroform, which dissolves out the bile 
coloring matter and shows more slowly and plainly the play of 
colors produced with the foregoing reagents. 

Tests for Bile Acids. — Add a few grains of cane sugar or glucose 

Fig. 59. 




Leucin Spherules and Tyrosin Needles. 



to the urine and underlay it with sulphuric acid. At the junction 
of the liquids a reddish-purple color appears. As other substances 
than bile-acids may produce this reaction, we must, in cases of 
doubt, before applying the test, evaporate the urine to dryness, 



391 If a yellow (decomposed) nitric acid is not at hand, an efficient one may 
be made by adding a bit of zinc to some pure, fresh nitric acid. 



208 



ESSENTIALS OF CHEMISTRY. 






dissolve in alcohol, filter, again evaporate to dryness, and redis- 
solve in water. 

Leucin and Tyrosin occur only in bile urine, for they attend 
destructive liver disease, especially acute, yellow atrophy and 
phosphorus-poisoning. They form yellowish crystalline deposits 
(Fig. 59) —leucin as spherules, with concentric striae, and tyrosin 
as sheaf-like bundles of fine needles. 

Cystin is a rare urinary sediment, a yellowish deposit of 
hexagonal plates (Fig. 60), not dissolved by heat or acetic acid, 
but readily by ammonia. It is a highly sulphurized body whose 
formation in the system is obscure. It sometimes forms calculi. 

Blood. — Hematuria (blood in urine) may occur as the result 



Fig. 60. 



Fig. 61. 




Cystin. 



Blood Corpuscles. 



of (a) some disease or injury of the genito-urinary tract, as 
acute nephritis, calculus, parasites, cancer, wounds, etc. ; (b) a 
depraved condition of the blood, as in scurvy, purpura and cer- 
tain infectious diseases ; (c) of a disturbance of the renal circula- 
tion, as in mental emotions, malarial paroxysms and cardiac ob- 
structions. 

Bloody urine, if acid, is of a smoky hue, or even of a dark red- 
dish brown ; if alkaline, of a brighter red. If coming from the 
kidneys the blood corpuscles are diffused through the urine ; but if 



PART III. CLINICAL CHEMISTRY. 2O0 

from the bladder or urethra, they may be in rouleaux, or even 
clots. Owing to the biconcavity of the corpuscles, their centers 
and peripheries alternate in brightness and shadow, as the object- 
glass is made to approach or recede. Their color and smaller 
size also serve to distinguish them them from pus corpuscles. In 
doubtful cases a minute drop of blood, taken from the finger 
with a needle, may be used for comparison. After urine con- 
taining blood has stood for some time, the corpuscles lose their 
regular outline and become shrivelled and angular. (See a in 
figure.) If the corpuscles are disintegrated and dissolved, we 
must test for blood coloring matters. 

The spectroscope offers the best means for their detection, but 
as physicians are seldom provided with that instrument, the fol- 
lowing is the usual test : Place the urine in a test-tube and shake 
up with equal volumes of tincture of guaiacum and ozonized 
ether or old oil of turpentine. If blood coloring matters are 
present, the precipitated resin is blue, instead of a dirty greenish- 
yellow. 

Pus occurs in the urine whenever there is suppurative inflam- 
mation in any part of the genito-urinary tract ; such urine is al- 
ways more or less turbid and albuminous. This turbidity may 
be distinguished from that due to urates or earthy phosphates, 
since heat, that would clear up the urates, and acids the phos- 
phates, only serve to increase the turbidity of purulent urine by 
coagulating its albumin. This turbidity is due to pus corpuscles, 
rounded, colorless, very granular cells, a little larger than red 
blood corpuscles and practically identical with mucous corpuscles 
and leucocytes, except that pus corpuscles oftener have more 
than one nucleus (Fig. 63.) 

If the urine is greatly diluted, or, better still, treated with 
acetic acid, the cells swell up, lose their granular appearance and 
become transparent (Fig. 63, a). Pus may be distinguished from 
mucus by : (a) it is always attended with albumin ; (b) treated 
with an alkali it forms a gelatinous mass (Donne's test; (c) it 
effervesces on addition of hydrogen peroxide. 



2IO 



ESSENTIALS OE CHEMISTRY. 



Pus is most conveniently estimated by sedimentation, especially 
with the centrifuge and noting its percentage of volume. 

Fat in such quantities as to float on the urine generally comes 
from the introduction of a catheter, or from foreign admixture. 
Fatty degeneration of kidneys, or leakage of a lymph vessel, or 
the opening of an abscess into the urinary tract may cause Lip- 
uria (fat in the urine). It occurs as minute, highly refracting 
globules of various sizes (see a in figure 62) ; but sometimes, es- 



Fig. 62. 



Fig. 63. 




Fat Globules. 



Pus Corpuscles. 



pecially in chylous urine, in more intimate emulsion (as at &,) 
the globules appearing under the microscope as mere specks. Pat 
may be recognized by its dissolving on addition of ether. 

Epithelia in the urine may come from any part of the genito- 
urinary tract. The accompanying cut shows the typical forms of 
cells coming from various situations. It is generally impossible to 
locate the origin of an epithelial cell beyond the vagina and blad- 
der, for their distinctive differences, but slight at best, are rendered 
still fainter by maceration in the urine. Renal epithelium comes 
from the uriniferous tubules, and are rounded and granular, and, 
unlike pus cells, they show their nuclei without acetic acid. They 
are usually associated with albumin and tube casts (Fig. 65), 
and therefore point to kidney disease. Though we cannot know 



PART III. CLINICAL CHEMISTRY. 



211 



from what site the epithelia come, we can judge fairly well the 
condition of the mucous membrane by the number and character 
of the cells thrown off. For in acute diffuse inflammation of the 
kidneys, they appear in great numbers, often adhering to renal 
casts, or to each other. In the more chronic lesions, these cells 



Fig. 64. 




(a) Epithelium from the human urethra; (5) vagina; (c) prostate; (d ) Cowper's glands; 
(e) Littre's glands ; <_/") female urethra; (j? bladder. 

are much disintegrated and more or less filled with oil globules. 
Tube Casts. — In hemorrhage from or inflammation of the kid- 
ney the urine usually contains microscopic casts, or moulds of the 
uriniferous tubules, formed by exudation, into the tubules, of coagu- 
lable material, which afterwards contracts, becomes loose, and is 
washed out with the urine. As these casts imbed and bring away 
epithelial cells, granular matter, fat globules, blood disks, etc., they 
are a valuable index to the condition of the tubules. They are de- 
scribed by clinicians as ( i) Epithelial casts (see upper portion of 



212 ESSENTIALS OF CHEMISTRY. 

Figure 65), are those bearing renal epithelium. They indicate 
desquamative nephritis. (2) Hyaline casts (shown in left-hand 
part of figure) are transparent and comparatively free from en- 
tangled material. They come from tubules whose epithelium is 
sound and adherent, or from those bereft of epithelium. In the 
latter case they are more solid in appearance {waxy casts) and 
indicate serious nephritis. (3) Granular caste are opaque from 
presence of granular debris. (4) Fatty casts (see largest cast in 
figure) are such as carry oil globules, either free or contained in 



Fig. 65. 




Epithelial Cells and Tube Casts. 



epithelial cells. They are proof of fatty degeneration of the kid- 
deys. (5) Blood casts contain blood corpuscles, and show that 
the haematuria is of renal origin. (6) Bacterial casts are com- 
posed of micrococci and show the nephritis to be of septic 
character. 

Casts, especially in a urine of high specific gravity, subside 
so very slowly that hours are required for them all to reach the 
bottom, and the urine may, in the meantime, especially in sum- 
mer, undergo such marked changes as to make them unrecogniz- 
able ; or they may become obscured with clouds of micro-organisms 
or other newly formed precipitates. Much of this difficulty is 



PART III. CLINICAL CHEMISTRY. 213 

now avoided by the use of the centrifuge, which does, and does 
better, in a few minutes what formerly required as many hours. 

The sediment should be removed with a pipette, placed in a 
shallow cell upon a glass slide, and examined under a cover- 
glass ; the clear hyaline casts are especially difficult to find and 
should be looked for under oblique illumination. Some advise 
the use of staining agents to better differentiate these from the 
clear urine. 

SPERMATOZOA occur in urine as a result of spermatorrhoea, 
nocturnal emissions, or coitus. They are liable to escape obser- 

Fig. 66. 




Spermatozoa. 

vation, for they subside slowly, and are very small and transparent. 
Under a high power they are seen to consist of a small oval cell 
with a tail-like prolongation. Iheir tadpole-like appearance is 
shown in Figure 66. They are motionlesss in urine, and remain 
for days unaltered. 

Micro-organisms. — The urine, though generally sterile when in 
the bladder, becomes, as soon as voided, a ready medium for the 
growth of the lower forms of life, the germs of which get in from 
the air or unclean vessels. Among others we may mention : ( i) 
yeast fungus which is usually seen during sporule stage as 
transparent oval cells, sometimes arranging themsselve in 



214 



ESSENTIALS OF CHEMISTRY. 



branches. It grows only in saccharine urine, though spores 
closely resembling it are seen in acid urine containing neither 
sugar nor albumin. (2) Sai cina is a fungus seldom found in 
urine, but more frequently in matters vomited during certain dis- 
eases of the stomach. The cells are arranged in cubes, resem- 

Fig. 67. 



b .. 




(a) Micrococci in short chains and groups; (6) sarcinae; (c) fungi from acid fermentation; 
{d) yeast cells from diabetic urine; (e) mycelium of a fungus. 

bling bales bound with cross-bands. The sarcinae shown at b in 
Fig. 67 are from the urine, smaller than those from vomited 
matters. 

3. Bacteria {little rods). This is the general term given to the 
minute, moving organisms invaiiably present in putrefying animal 
and vegetable matter. They consist of simple cells filled with a 
colorless fluid and presenting several varieties of form : {a) 
micrococci appearing as trembling points, distinguished from 
other particles by their progressive motion; (b) rods about the 



PART III. CLINICAL CHEMISTRY. 215 

length of the diameter of blood disks, sometimes at rest, but 
usually vibrating across the field, (c) Vibriones, consisting of 
several rods joined together and moving with greater rapidity ; 
and (d) ZooglecE, aggregations of bacteria held together by gela- 
tinous material and resembling masses of amorphous urates or 
phosphates. These various forms are shown in Figures 45 and 
46. Bacteria not only cause decomposition outside, but may set 
it up in urine while yet within the bladder, provided they are in- 
troduced from without. This may be done by dirty catheters 
and sounds, or they may work their way down the urethra in the 
pus of a gleet. The ammoniacal fermentation thus set up soon 
induces cystitis. The characteristic microbes of various diseases 
have been observed. The " bacillus tuberculosis" is most fre- 
quently found and easily demonstrated by staining the sediment 
in the ordinary way and is of great clinical importance, as it is 
certain evidence of tubercular ulceration of the bladder or other 
portions of the urinary tract. 

Extraneous Bodies, such as hair, wool, or fragments of feathers, 
are often found in urinary deposits, and ludicrous mistakes have 
been made by observers not on their guard for such casual ad- 
mixtures. 

Urinary Calculi. — Urinary calculi (calculus, a pebble) are 
composed of urinary sediments which have gathered around some 
nucleus (usually calcium oxalate or uric acid crystals or some for- 
eign body) within the bladder, and being slowly deposited, par- 
ticle upon particle, and layer upon layer, the concretion becomes 
as hard as stone. Calculi are not always composed of the same 
material throughout, but often consist of successive layers of dif- 
ferent sediments deposited during varying conditions of the urine. 

The qualitative analysis of calculi is easy. Saw the stone 
through the middle, and see whether it is composed of the 
same material throughout or of successive layers of different sed- 
iments. If the former, take the sawdust; if the latter, chip off a 
specimen from a single layer. This should be pulverized very 
fine (for it is dissolved much less readily than fresh sediments), 



2l6 ESSENTIALS OF CHEMISTRY. 

and then tested by means of heat, acetic and hydrochloric acids ; 
for in the great majority of cases it will be found to consist of 
urates, phosphates, calcium oxalate or uric acid. Place the pow- 
der in a test-tube, and add 5 Cc, of water; boil, and if it dis- 
solves it is urates. If not, add acetic acid, and warm again ; if it 
dissolves it is phosphates. If not, boil with hydrochloric acid; if 
it dissolves, it is calcium oxalate. If not, it is uric acid, which 
may be confirmed by the murexid test. 
The following method is easier and surer : 

I. Heat to redness on a piece of platinum foil. If no residue, 
see II ; if a residue, see III. 

II. To a fresh portion apply the murexid test. If it responds 
it is ammonium urate, or uric acid ; if it does not respond, it is 
cystin or xanthin, see IV. 

III. To the residue, when cool, add hydrochloric acid. If it 
effervesces it is an oxalate or urate, which may be determined by 
the murexid test ; if it does not effervesce, it is a phosphate. 

IV. Dissolve some of the powder in nitric acid. If the solution 
is yellow it is xanthin ; if dark brown it is cystin. 

MILK. 

Female mammalia all possess certain glands (mammary) that 
secrete, for the nourishment of their young, an opaque white fluid 
called milk. 590 It possesses a peculiar odor, often quite character- 
istic of the animal from which it is derived. Its opacity is due to 
minute globules of fat, or butter, each more or less surrounded by 
an albuminoid envelope and suspended in the fluid and presenting 
under the microscope m the appearance shown in figure 68. 

In the colostrum, which is the name given to the milk secreted 

390 procure a liberal supply of ordinary milk at least three hours beforehand 
and let it stand. Siphon off the lower two-thirds and label it "skim milk" 
and the residue " cream." Procure another supply of fresh milk just before 
the exercise opens. 

391 Examine a drop of milk with a microscope. 



PART III. — CLINICAL CHEMISTRY. 



217 



during the first few days after parturition, these albuminoid en- 
velopes are seen to be large epithelial cells (colostrum cells) 
undergoing fatty degeneration and completely enclosing the fat 
globules. 



Fig. 68. 



Milk. 




Colostrum. 



(Holland.) 



The reaction 392 of cow's milk is often acid, but that of woman's 
milk should be feebly alkaline. Milk, when exposed to the air, 
soon undergoes the lactic acid fermentation (sours), thus, 
C 12 H 22 O n + H 2 = 4 H 2 C 3 H 4 3 . 

The specific gravity :m varies from 1029 to 1035. The quan- 
tity of milk an animal will secrete depends upon the health, food, 
drink, etc. A woman should secrete about one liter, while a good 
cow should produce about ten times as much. 

Composition. — The milk of all animals consists of water hold- 
ing in solution casein, albumin, sugar and mineral salts, and sus- 
pending globules of fat. It is the only perfect food, especially 
for the young. 



892 Test the reaction with red and blue litmus papers. 

39H The specific gravity may be measured with the ordinary urinometer dis- 
tributed to the students, but the teacher should exhibit a lactometer, Fig. 69. 

is 



2l8 ESSENTIALS OF CHEMISTRY. 

The composition of milk varies with the species and breed of 
the animal and with the individual. Even in the same individual 
it varies with the health, food, manner of living, period of lac- 
tation and many other circumstances. 

Woman's and cow's milk are the most important. The follow- 
ing table (Konig ) shows their comparative composition : 

Analysis of Human Milk and Cow's Milk (Kcnig). 

Woman's Milk. i Cow's Milk. 

Mean. Minimum. Maximum. Mean. Minimum. Maximum 



Water 37.09 83.69 90.90 

Total solids 12.91 9.10 16.31 

Fat 3.90 1. 71 7.60 

Milk sugar 6.04 4.11 7.80 

Casein 0.63 0.18 1.90 



87.41 80.32 91.50 

11.59 8.50 19.68 

3.66 1. 15 7.09 

4.92 3.20 5.67 

3.01 1. 17 7.40 



Albumin 1.31 0.39 2.35 0.75 0.21 5.04 

Albuminoids 1.94 0.57 4.25 3.76 1.38 12.44 

Ash 0.49 0.14 ? ! 0.70 0.50 0.78 

Proteids. — Of these by far the most important and interesting 
is casein, though there is a small amount of albumin and globu- 
lin ; but these latter are so similar to serum albumin and serum 
globulin as to need no special description. 

Casein. — It is claimed that the casein is not in actual solution ; 
but if not, it is suspended in such a loose, thin, liquid condition 
that it flows and drips as a solution. The casein seems to be held 
in solution by calcium phosphate, and some call it caseinogin, 
reserving the name casein for the coagulated substance. It does 
not coagulate on boiling, 394 the scum foiming on the surface being 
coagulated albumin. It dissolves readily in alkalies and is often 
compared with alkali-albumin ; is easily coagulated by acids, 395 and 
most easily by the stomach ferment, known to cheese-makers as 



SB * Boil a sample of skim milk and note that the casein is not coagulated, 
but a scum of albumin forms. 

395 To another sample add a few drops of acetic acid and note that the casein 
is coagulated, but that it dissolves on addition of an alkali; to be reprecipi- 
tated on addition of more acid, and so on. 



PART in. CLINICAL CHEMISTRY. 219 

rennet, 896 one part of which will coagulate several hundred thous- 
and parts of casein. 

In mother's milk the coagulum is flocculent and easier of diges- 
tion ; while in cows' milk it is in firmer clots and more indigestible, 
but it may be made somewhat easier of digestion if the milk is 
previously boiled or alkalinized or diluted with some gelatinous 
substance. 

The clear fluid that separates from the coagula is known as 
whey™' and is of considerable nutritive value, since it contains all 
the constituents of the milk except the casein and entangled fat 
globules. 397 

Fat. — The fat globules of milk contain also traces of cholester- 
ine, of lecithin and of a yellow coloring matter closely allied to the 
lutein of yolk of tgg. The albuminoid envelopes previously men- 
tioned are broken in the process of churning, and the fat globules 
coalesce in lumps, forming butter. 

The butter may be also extracted with ether, 399 and without 
churning, provided the milk be previously treated with alkali or 
acetic acid to dissolve away the albuminoid envelopes. 

Milk Sugar. — (Lactose.) 400 — This has already been mentioned 
with the other carbohydrates ; it differs from them, however, in 
fermenting into lactic acid, a reaction that occurs spontaneously 
whenever milk is exposed to contamination from the air and al- 
lowed to stand at ordinary temperatures. The lactic acid thus 



396 Warm some milk in a beaker to blood-heat and add a few drops of ex- 
tract of rennet or essence of pepsin, and note that in a few moments the milk 
is coagulated and that a clear liquid separates from the curd. 

397 Remove the fluid by filtration and label " whey." 

:i98 Take successive portions of the whey and test with the xanthoproteic 
reaction, Millon's reagent, etc. 

'"Take some milk in a test-tube, add a little alcohol and caustic potash, and 
shake with ether. Pour off the ether into a dish and evaporate it; butter is 
left behind. Notice also the characteristic smell of butyric ether, especially if 
a few drops of H 2 S0 4 be added. 

400 Test the whey for lactose by the alkali-copper and other tests described 
elsewhere. The teacher should show some practical work with the creamo- 
meter and lactoscope. 



2 20 ESSENTIALS OF CHEMISTRY. 

produced quickly coagulates the casein and the milk "sours" and 
becomes " clabber." 

This fermentation is due normally to the implantation of the 
bacillus acidi lactis; which rapidly proliferates unless the milk is 
kept very cold or treated with antizymotics. Occasionally milk 
is contaminated with other bacteria, especially the bacillus cyano- 
genus, and, turning blue, slimy and bitter, developes tyrotoxicon, 
the poisonous alkaloid which has been responsible for so many 
deaths. 

To prevent these fermentations various methods have been 
used ; that of refrigeration has been employed since time imme- 
morial ; and milk kept cold will remain sweet for days, but in 
spite of the greatest care the ferment will gain access and remain 
to set up fermentation in the child's stomach and disturb its di- 
gestion. To prevent this, the milk may be boiled ("sterilized 
milk"), 401 but the high heat coagulates the albumin and globulin, 
and impairs the casein ; and children fed on this milk do not 
thrive. By heating the milk to not over 75° C, or 167 F. ("pas- 
teurization") these changes in the proteids do not occur, though 
many of the organisms are destroyed, and others so weakened 
that the milk does not readily spoil, and is much less likely to 
disagree with the infant. 

Salts. — These consist mainly of phosphates of calcium, magne- 
sium, sodium and potassium, with the chlorides of sodium and 
potassium and a trace of iron. 

Adulteration. — Of the many ways of adulterating milk, the 
most common methods are, (a) chemicals, employed mainly as 
preservatives, such as salicylic acid, sodium carbonate or borate ; 
the two latter neutralizing the lactic acid and delaying the coagu- 
lation ; (b) skimming off the cream, or fatty layer, that gathers at 
the top of milk when allowed to stand. This not only deprives 



401 Let the student boil some milk in a test-tube, then close it with a plug of 
dry absorbent cotton and set it aside to note that it remains sweet and unaltered 
for days and weeks. The teacher should also show some standard sterilizer, as 
Arnold's. 



PART III. — CLINICAL CHEMISTRY. 



221 



the milk of a valuable constituent, but, unless the new and rapid 
centrifugal process is used, delays its delivery for at least half a 
day, thus increasing the danger of contamination and decompo- 
sition \ (c) dilution?® 1 which is a very common practice, but less 
dangerous to health, unless the water is contaminated with 
typhoid or other infectious germs. 

Milk Testing. — The specific gravity of good milk should not 
be below 1029 unless the milk is unusually rich in fats, which being 
lighter than the rest of the milk, lowers the specific gravity \ and 
if it rises above 1035 the milk has probably been skimmed. 



Fig. 69. 



Fig. 70. 



d 



j> 




Iro- Creamo- 
:er. meter. 

(Starr.) 



Feser's Lactoscope. 
(Queen.) 



Skim milk, however, may be so diluted as to bring its specific 
gravity within the ordinary limits, but an experienced eye can 
readily see that instead of being white, the milk assumes a bluish 
tinge, or in other words loses the natural opacity imparted by 
the suspended oil globules. So the measurements of the specific 

402 Let the student dilute a specimen of milk in a test-tube or beaker, and 
note the bluish tint produced. 



2 22 ESSENTIALS OF CHEMISTRY. 

gravity are not conclusive unless the opacity be also observed : This 
is easily done by the lactoscope (Fig. 7o), 40H which consists of a 
cylinder of clear glass (A), containing at the lower part a smaller 
cylinder of white glass (resembling that shown at x, fig. 70), upon 
which are a few black lines. In testing, 4 Cc. of the milk are intro- 
duced from the graduated pipette {B)^ and the black lines are en- 
tirely concealed by the opaque milk ; pure water is then gradually 
added with shaking until the milk is clear enough for the black lines 
to be visible. The level of the diluted milk in the cylinder is then 
read off in the graduations as percentage of fat in the original sam- 
ple. This method is quick, accurate and reliable, unless the milk 
be adulterated with some suspended white powder, as chalk or 
starch, in which case the microscope will disclose its nature. 

A simple but rough estimate of the cream may be made by 
allowing the milk to stand over night in a graduated cylinder 
such as the creamometer shown in Fig. 69. 404 

"Wit centrifuge (Figs. 71 and 72) with milk-tubes and a volume- 
pipette (Fig. 73) affords a very quick and fairly accurate method 
of estimating the quantity of fats. Add to each milk-tube 5 Cc. of 
the milk, 1 Cc. of the HC1 solution (hydrochloric acid, 50 vol- 
umes ; methyl alcohol, 13 volumes ; fusel oil, 37 volumes) ; shake 
well and add strong sulphuric acid (sp. gr. 1.83) drop by drop 
with constant shaking until tube is filled to the zero mark. Ro- 
tate for two minutes and read the percentage of fats directly from 
the scale. As the graduations extend only to 5 per cent., a milk 
richer than this must be diluted, and the reading multiplied ac- 
cording to the dilution. 

The above methods of estimating the amount of fat, although 
very useful, are not sufficiently reliable and accurate for official 
inspection. Milk may vary in consistence as well as in composi- 
tion, so that one specimen may furnish more cream than another 



40i The teacher should show actual work with a creamometer and lactoscope. 
404 Let each student chew a piece of paraffine and collect the saliva in a 
beaker. 



PART III. — CLINICAL CHEMISTRY. 



223 



containing twice as much fat. For accurate work, the Werner- 
Schmidt process is very convenient, viz., take 10 Cc. of the milk 
and 10 Cc. of strong HO ; pour into a long test-tube of about 
50 Cc. capacity. Bring the mixture to a boil ; when cool add 10 
Cc. of ether and shake well ; as soon as the ether has all risen to 



Fig. 71. 



Fig. 72. 



Fig. 74. 







fi=* 



If 



Fig. 73. 





the top, remove the cork and insert the perforated cork and tube, 
as shown in figure 74. 

By sliding the exit tube down until it opens just above the line 
of separation, the ether solution of the fat can be blown into a 
previously weighed beaker ; another portion of ether is added to 
the test-tube, shaken and blown out as before, repeating the pro- 
cess two or three times. The ethereal solution is now evaporated 
over a water-bath and the beaker weighed. The amount of fat 
thus obtained represents that contained in 10 Cc. of milk and 
shows the percentage. 



224 ESSENTIALS OF CHEMISTRY. 

Clinical Test of breast milk is generally neglected by the prac- 
titioner, though it has been long recognized that the milk of dif- 
ferent women, or even of the same woman under different condi- 
tions, health, diet, exercise, etc., often disagrees with the nursling. 
Dr. Emmet Holt, of New York, who has made extensive studies 
along this line, has shown that these clinical variations are attended 
by, and possibly caused by, variations of specific gravity, reaction 
and percentage composition. The specific gravity of human 
milk should range from 1028 to 1033 and the quantity cream 
from 3 to 4 per cent. 

Kumyss is the name given to milk fermented under the influ- 
ence of a peculiar ferment, originally imported from Southern 
Russia. The lactose is made to undergo the vinous fermentation, 
producing alcohol and carbon dioxide in the presence of the 
yeast plant. It is a valuable stimulant and food stuff in malnu- 
trition and wasting diseases. 

SALIVA. 

Human saliva is a viscid, tasteless, opalescent, alkaline fluid, the 
product of the salivary glands. 404 Its active principle is pty aline, 
the function of which is to convert starches into glucose. 405 
It acts best in neutral reaction \ strong alkalies or acids retard or 
even destroy it. Saliva also contains potassium sulpho-cyanate, 406, 
the function of which is unknown. 



405 Put some saliva with a few drops of starch solution in four test-tubes and 
label a, b, c and d. To a add two drops of HC1; to b five drops of liquor 
potassse; boil c. Set all four test-tubes in a beaker of water; warm no hotter 
than the hand can easily bear. After ten minutes remove and test each tube 
for starch and sugar. It will be found that only in d has the ptyaline con • 
verted the starch into glucose, for acids and alkalies restrain the ptyaline, and 
boiling destroys it. 

406 To some saliva in a test-tube add a drop of ferric chloride, a blood-red 
color indicates potassium sulpho-cyanate. 



PART III. CLINICAL CHEMISTRY. 225 

GASTRIC JUICE. 

Gastric juice is a thin, yellowish, sour licruid, of specific gravity 
seldom over ioio, and of somewhat variable composition. It may 
be obtained fairly pure from man and other animals, through gas- 
tric fistulae or more usually the stomach-pump, or stomach-tube. 
It is secreted and reabsorbed in surprising quantity, a man pro- 
ducing from fifteen to thirty pounds a day. 

Its composition may be stated as 

Water 99-44 

Pepsin and other organic matter 32 

Hydrochloric acid 25 

Sodium chloride 14 

Potassium chloride 05 

Calcium chloride 006 

Calcium and magnesium phosphates 015 

100.221 

Pepsin is a ferment that in connection with acids has the prop- 
erty of converting, by a process of hydration, the albuminoids into 
albumoses and finally into peptones, making them osmotic and 
capable of being taken up by the vessels of the stomach. It 
digests only nitrogenous food, the oils, fats, starches and sugars 
being unaffected by it. The process is retarded by too little or 
too much acid and by alcohol. The pepsin does not seem to be 
destroyed in the process, but continues to act almost indefinitely, 
digesting large quantities of the proteids. Its acidity is due 
mainly to hydrochloric and certain organic acids, as lactic, 
butyric and acetic, but these latter are incidental and mainly the 
result of fermentative action. 

Clinical examination of gastric juice is becoming each year a 
more and more important means of diagnosis in stomach diseases. 
The usual method is, first to thoroughly wash out the stomach 
with warm water and, some hours afterward, administer a test- 
meal. This is usually a light breakfast consisting of an ounce 
and a-half of dry roll and eight ounces of water, or weak tea 



2 26 ESSENTIALS OF CHEMISTRY. 

without milk or sugar. To insure thorough mastication and sali- 
vation twenty minutes should be occupied in consuming the meal, 
and the water or tea stfould be drunk last. One hour afterwards, 
the secretion of HCl (one of the two chief agents in proteid di- 
gestion) being at its maximum, the remains of the liquefied food 
are drawn off and examined, first ocularly to determine the degree 
of disintegration and solution. Normally, all of the nine and one- 
half ounces of the test-breakfast, with the exception of one and 
one-third ounces, should be absorbed, or passed into the small 
intestines at the end of an hour. If a larger amount is found it 
indicates slow absorption ; if a smaller, more rapid absorption 
than normal. The stomach contents, light yellow in color, are 
then filtered, and the filtrate examined according to the following 
scheme : 

Filtrate of stomach contents after a test-bteakfast. Color clear 
yellow. 

Qualitative Tests. — 

(i) Litmus test— 7 reaction acid (red). 

(2) Free acid, Congo-red, test — very delicate, reaction blue. 

(3) Free HCl, Gunzburg's test, Boas's test — reaction car- 

mine red. 

(4) Lactic acid, Uffelman's test — reaction greenish yellow. 

(5) Rennet ferment, Milk test — coagulation. 

(6) Butyric acid — decolorizes Uffelman's reagent. 
( 7) Acetic acid, odor test. 

Quantitative Tests. — 

(8) Estimation of total acidity by saturation. 

(9) Esti?nation of free HCl by Leo's method. 

(10) Estimation of acid salts by Leo's method. 

( 1 ) Litmus test. — Tested with litmus paper, the reaction should 
be acid, turning the paper red. 

(2) Congo-red test. — Add a few drops of this dye to a portion 
of the stomach fluid. Free acids if present change it to sky-blue j 
acid salts produce no change. 



PART III. — CLINICAL CHEMISTRY. 2 2^ 

(3) Free HCL — To determine the presence or absence of this 
is of great importance to the physician, as it is as necessary for 
digestion as the pepsin itself, and its variation more important in 
diagnosis, e. g., between cancer, in which it is diminished, and 
gastric ulcer, in which it is increased. 

r Phloroglucin . . 2 gr. 
(a) Gunzburg's reagent 1 Vanillin .... 1 gr. 
(.Absolute alcohol . 30 gr. 
A drop of this solution is added to a few drops of gastric juice 
and gently warmed. If free HC1 be present in the smallest 
amount a red color is produced, and cherry-red crystals de- 
posited. 

c Resorcin (resublimed) . . 5 gr. 

(b) Boas's reagent -j Sacchar. alb 3 gr. 

L Spiritus dilut 100 gr. 

This test is about as delicate as the preceding and its ingre- 
dients not so rare and expensive. A few drops of the solution 
added to a little gastric juice in a dish and gently warmed pro- 
duces a red color if free HC1 be present. 

4. Uffelman's test. — Add to 5 or 10 Cc. of a 2 to 5 per cent, 
solution of carbolic acid, 1 or 2 drops of ferric chloride solution 
and dilute with water till the solution assumes a beautiful 
amethyst-blue color ; to this add a portion of the stomach fluid ; 
a change to canary or greenish-yellow indicates lactic acid. 
This test is extremely delicate, holding for a 1 in 20,000 solution 
of lactic acid. Be careful to ascertain whether the patient has 
taken any wine or alcohol preceding the test, as either of these 
will give the same reaction. 

(5) Rennet ferment, milk test. — Take a small quantity of boiled 
milk, say 10 Cc, having a neutral reaction, and add an equal 
amount of carefully neutralized filtered stomach contents. The 
mixture is then placed in a warm chamber at 100 F., and in 10 
or 15 minutes the milk has coagulated and separated into a cake 
of casein and clear whey. 



2 28 ESSENTIALS OF CHEMISTRY. 

(6) Butyric acid decolorizes Uffelman's reagent. If present in 
large quantities, its acrid, rancid odor is manifest. 

(7) Acetic acid. — The best practical test for this acid also is 
the nose. If present in considerable quantity it has an unmistak- 
able odor. 

(8) Total acidity. — The method of measuring this is simple. 
A burette is filled with a decinormal solution of caustic soda : 5 
or 10 Cc. of filtered stomach contents are poured into a small 
glass beaker, and 1 or 2 drops of a (1 per cent.) alcohol solution 
of phenol-phthalein are added. The solution in the burette is 
very gradually added until the red color is just permanent. The 
number of Cc. of the alkaline solution used represents the acidity 
of the quantity of stomach contents employed. Normally the 
acidity of 10 Cc. of the stomach contents, obtained one hour after 
the test breakfast, is from 4 to 6 Cc. ; results below or above this 
are pathological. 

(9) Estimation of free HC/.—This, provided no other free 
acids are present, is determined by adding pure chalk, which will 
neutralize the acidity if due to free acid, but has no effect on acid 
salts. The difference in acidity before and after the addition of 
the chalk represents the physiologically active HC1. To separate 
the organic acids, first extract with ether, by thoroughly shaking 
about 5 to 10 Cc. of the stomach contents in a medicine bottle 
with alcohol-free ether ; let the ether separate, which usually 
occurs very rapidly, and pour off in a small glass beaker. This is 
repeated until about 30 to 60 Cc. of ether has been used. The 
ethereal extract contains the organic acids. 

(10) Acid Salts. — The last determination of acidity in the pre- 
ceding test represents the quantitative estimate of acid salts. 



PART III. CLINICAL CHEMISTRY. 229 

FERMENTS. — These are certain nitrogenous bodies, animal and vegetable, 
of unknown constitution, which by some means, not clearly understood, cause 
many organic compounds to decompose, with the production of other and 
simpler substances, the ferments themselves being unaffected. Ferments are 
of two classes : Organized and Unorganized Ferments. 

1. The Unorganized or Soluble Ferments. — Among these are: (a) 
diastase or malti?i, appearing in the sprouting of grain, and formed from the 
gluten; it serves to convert the starch of the seed into glucose. Malt, which 
is sprouted barley, contains it in abundance, and is used to convert meal 
(starch) into glucose for fermentation in the manufacture of alcoholic liquors, 
and in medicine as a digestive agent. The ptyalin of saliva and a pancreatic 
ferment act like diastase, (b) pepsin, of the gastric juice, and (c) trypsin, of 
the pancreatic fluid, both of which serve to convert the albuminoids into pep- 
tones, the one in acid and the other in alkaline solution. 



Fig. 75. 




YEAST CELLS. 



2. Organized Ferments. — When their spores are carried by the atmos- 
phere, or otherwise, into a suitable fermentable liquid, viz., one containing 
albuminoid substance, and kept warm (68 to 105 F.), these ferments grow and 
proliferate wiih great rapidity, inducing fermentative changes in a few hours. 
The most important of these ferments are : (a) Yeast (torula cerevisice, or 
saccharomyces eerevisice), shown in figure t>&- This converts glucose into 
alcohol and carbon dioxide (vinous fermentation); (b) acetic acid fer?nent 
(ijiycoderma aceti), commonly called " mother of vinegar," grows on solutions 
containing alcohol, which it helps to oxidize into acetic acid; (c) mucor 
mucedo, which causes alcoholic fermentation; (d) thrush fungtis (oidium 
albicans) grows within the mouths of ill-kept children. It induces a slight 
alcoholic fermentation; (e) lactic and butyric ferments go together, the one 
preceding and the other closely following. These fermentations occur in 
intestinal indigestion, and the gas evolved produces flatulent colic. 

Putrefaction (the spontaneous decomposition of nitrogenous organized 
bodies) is accompanied, if not caused by micro-organisms, usually bacteria. 
Decay, on the other hand, is the gradual decomposition of organic bodies by 
the slow action ot oxygen, and does not depend on living organisms. 

Fer?nentation Experime7it. — Before leaving the laboratory exercise, make a 
mixture of thin starch paste, crushed malt grains, and a bit of yeast. Put into 
a side-necked test-tube with its mouth corked, and the delivery tube dipping 
into a bottle of lime water. Next day note that the mixture has fermented, or 
is fermenting, and that the CO., evolved has bubbled out through the lime 
water, precipitating CaC0 3 , and that the mixture is now alcoholic. 



230 



ESSENTIALS OF CHEMISTRY. 



TABLE OF METRIC MEASURES. 



Fig. 76. 



pm 



IIIII1II I HI 



tlll[lt-||ltlM!ll|IMIIIllll. i |tll l |llll| l ll i| iiii |ii iijjiii|jiij| 



mum 



w 



10 



The Decimetre. 



MEASURES OF LENGTH. 



Millimetre 

Centimetre 

Decimetre 

Hetre 

Decametre 

Hectometre 

Kilometre 

Myriametre 



= 0.001 of a metre. 

= 0.010 of a metre. 

= 0.100 of a metre 

= 1.000 Hetre 

= 10.000 metres. 

= 100,000 metres. 

= 1000.000 metres 

= 10,000.000 metres 



= about 4 inches. 
= 39.37 inches. 



= about % of a mile. 
= about 6% miles. 



Centaire 

Are 

Hectare 



MEASURES OF SURFACE. 

1 square metre = about i£ square yards 

100 Square Metres. 

10,000 Square metres. = about 2%, acres. 



MEASURES OF VOLUME. 

Cubic centimetre = 0.001 of a litre. 

Litre (cubic decimetre) = 1000. cubic centimetres. 

Cubic metre = 1000. cubic decimetres. 

Cubic metre = tooo. litres, or 1 kilometre. 

Cubic metre = 1 stere. 



MEASURES OF WEIGHT. 

1 Milligramme = 0.001 of a gramme = about -Q-g of a grain. 

1 Centigramme = 0.010 of a gramme. 

1 Decigramme = o. too of a gramme. 

1 Gramme = 1.030 Gramme = about 15% grains. 

1 Decagramme = 10.000 grammes. 

1 Hectogramme — 100 000 grammes. 

1 Kilo(gramme) == 1000.000 grammes = about 2! lbs. 

1 Tonneau = ic 



kilos 



= about 1 ton. 



INDEX. 



Absolute weight, 10 
Acetamide, 170 
Acetanilide, 171 
Acetic aldehyde, 152 
Acetone, 145, 205 
Acetylene, 100, 139 
Acid, acetic, 153, 228 

antimonic, 70 

antimonious, 70 

arsenic, 63 

arsenous, 64 

benzoic, 161 

boric or boracic, 107 

butyric, 154, 228 

cathartic, 169 

carbazotic, 161 

carbolic, 159 

carbonic, 75 

chloric, 41 

chlorous, 41 

chromic, no 

citric, 158 

cyanic, 80 

diacetic, 205 

diatomic, 157 

diabasic, 157 

formic, 145, 153 

gallic, 162 

hippuric, 192, 206 

hydriodic, 41 

hydrobromic, 41 

hydrochloric, 41 

hydrocyanic, 41 

hydroferri cyanic, 80 

hydroferrocyanic, 80 

hydrofluoric, 41 

hydrosulphuric, 46 

hypochlorous, 41 

hyponitrous, 57 

hypophosphorous, 63 

lactic, 158, 219 

lithic see Uric), 192 

malic, 158 

mecomic, 179 

metaphosphoric, 62 

muriatic, 41 

myronic, 169 

nitric, 59 

nitrohydrochloric, 41 

nitromuriatic, 43, 128 

nitrous, 58 

oleic, 155 

orthophosphoric, 63 

osmic, 129 

oxalic, 157 

palmitic, 155 



Acid, pentylic, 154 

perchloric, 41 

phenic, 159 

phenvlic, 159 

phosphoric, 63 

phosphorous, 63 

picric, 161 

prussic, 79 

pyrogallic, 162 

pyrophosphoric, 62 

salicylic, 162 

silicic, 81 

sodium phosphate, 90 , 185, 195 

stearic, 155 

succinic, 158 

sulphocarbolic, 160 

sulphocyanic, 80 

sulphuric, 50 

sulphurous, 49 

tannic, 169 

tartaric, 158 

tetrylic, 154 

uric, 192 

valerianic, 154 

xanthoproteic, 172 
Acidimetry, 96 
Acid salts, 91 
Acids, aromatic, 161 

definition of, 40 

fatty, 154 

organic, 153 
Aconitine, 179 
Affinity, chemical, 32 

precedence of, 32 
Agate, 81 

" Aging " of liquors, 147 
Air, S3, 77 
Albumin, 198 

acid, 174 

alkali, 174 

derived, 174 

egg, 173 

serum, 173 

vegetable, 173 
Albuminates, 174 
Albumins, natural, 173 
Albumoses, 175, 200 
Alcohol, 144 

absolute, 146 

amylic, 148 

butyl, T48 

derivatives, 144 

ethene, 157 

ethyl, 146 

glyceryl, 159 

methyl, 145 



(*3') 



232 



INDEX. 



Alcohol, pentyl, 148 

propyl, 148 

radicals, 157 

sulphur, 148 

tetryl, 148 

trityl, 148 

vinic, 146 

wood, 145 
Aldehyde, 152 

acetic, 152 

ethyl, 152 

form-, 152 

par-, 152 
Aldehydes, 145, 151 
Ale, 147 

Algaroth, powder of, 70 
Alkalies, organic, 175 
Alkalimetry, 96 
Alkaloids, 175 
Allantoin, 192 
Alloys, 82 
Allotropic forms, 81 
Allylsulphocyanate, 168 
Allotropism, 137 
Aluminum, 107 

chloride, 108 

group, 106 

hydrate, 108 

oxide, 108 

silicates, 109 

sulphate, 108 
Alum, 108 
Alumen, 108 

exsiccatum, 109 
Amalgam, 82, 121 
Amber, 158 
Amethyst, 81 
Amides, 169, 175 
Amines, 169, 175 
Ammonia, 55 

fountain, 56 

liquefied, 56 

type, 169 
Ammoniac, 141 
Ammoniated mercury, 123 
Ammonii carbonas, 88 
Ammonio-citrate of iron, 117 

ferric alum, 109 

magnesium phosphate, 103, 195 

nitrate of silver, 66 

sulphate of copper, 66 

tartrate of iron, 66 
Ammonium, 87 

bicarbonate, 88 

carbonate, 88 

cyanate, 80, 133, 188 

hydrate, 87 

hydrosulphide, 88 

molybdate, 118 

nitrate, 58, 87 

nitrite, 53 
Amygdalin, 80, 168 
Amy! acetate, 154 

hydrate, 148 

nitrite, 151 
Amyl alcohol, 148 
Amyloses, 163 
Amylum, 164 



Analysis, 26 

acidulous radicals, 131 

definition of, 26 

metallic radicals, 130 

ultimate, 135 
Aniline, 170 
Animal charcoal, 74 
Antifebrin, 171 
Antimonious chloride, 69 

hydride, 69 

•oxychloride, 70 

oxide, 70 

sulphide, 70 
Antimoniuretted hydrogen, 69 
Antimony, 69 
Antimony and potassium tartrate, 

70 
Antimony, butter of, 69 
Antimonyl, 70 
Antipyrine, 171 
Antiseptics, 54 
Antitoxine, 178 
Antizymotics, 54 
Anuria, 182 
Apomorphine, 179 
Aqua, 26, 87 

ammonia, 87 

ammoniae fortior, 38 

chlori, 38 

destillata, 30 

fortis, 59 

regia, 43, 128 
Arbutin, 169 

Archimedes, principle of, n 
Argenti nitras, 126 
Argol, 158 
Argon, 55 
Arsenic, 63 

oxide, 65 

pentoxide, 65 

toxicology of, 65 

white, 64 
Arsenical mixtures, 66 

poisoning, 66 
Arsenous hydride, 64 

iodide, 64 

oxide, 64 

sulphide, 64 
Arseniuretted hydrogen, 64 
Arsenum, 63 

oxides and acids, 64 
Arsine, 64 
Artificial parchment, 163 

products, 133 
Assafoetida, 141 
Asbestos, 81, 102 
" -ate," 36 
Atmosphere, 53 
Atomic theory, 15 

• weight, 16 
Atoms, 16 
Atropine, 179 
Auric chloride, 129 
Auri et sodii chloridum, 129 

Babbitt's metal, 69 
Bacillus acidi lactis, 220 
cyanogenus, 220 



INDEX. 



2 33 



Bacteria, 214 
Bacterial proteids, 178 
Baking powders, 90 
Baking soda, 90 
Balloons, 20 
Balsam of Peru, 141 
Balsams, 141 
Barium, 101 

chromate, 102 

sulphate, 101 
Bases, 18 

Basylous radicals, 32 
Beer, 147 
Beet sugar, 166 
Bengal light, 101 
Benzaldehyde, 168 
Benzene, 142 

series, 141 
Benzine, 138 
Benzoin, 141 

Bichloride of mercury, 123 
Bichromates, in 
Bile in urine, 206 
Bilirubin, 206 
Bismuth, 71 

ammonio-citrate, 72 

nitrate, 71 

oxynitrate, 71 

subcarbonate, 71 

subnitrate, 71 
Bismuthyl, 70 
Biuret reaction, 172, 201 
Black lead, 73 

oxide of copper, 119 

oxide of manganese. 21, 38, in 

oxide of mercury, 124 
Black wash, 124 
Bleaching, 31, 39, 90 

powder, 99 
Blondine, 31 
Blood, 208 

Blood casts in urine, 212 
Blue ointment, 121 

pill. 121 

vitriol, 119 
Bluestone, 119 
Boas' reagent, 227 
Boiling point of water, 26 
Boroglyceride, 107 
Borax, 107 
Boron, 106 
Brandt, 60 
Brandy, 147 
Brass, 104 
Brazing, 107 
Brimstone, 45 
Britannia metal, 69 
British gum, 164 
Bromides, test for, 43 
Bromine, 37, 136 
Bromoform, 143 
Bromum, 37, 136 
Bronze, 118 
Brucine, 179 
Burette, 97 
Butter, 219 

of antimony, 69 
Butyl, 144 



Cadaverine, 178 
Cadmium, 106 
Caesium, 96 
Caffeine, 179 
Calcined magnesia, 103 
Calcium, 98 

carbide, 10c, 140 

carbonate, 98, 206 

chloride, 98 

group, 97 

hydrate, 99 

hypochlorite, 99 

oxalate, 99, 205 

oxide, 98 

phosphate, 99 

sulphate, 99 
Calculi, urinary, 205, 215 
Calomel, 123 
Calx, 98 

chlorata, 99 
Camphor, coal tar, 142 

monobromated, 141 
Camphors, 140, 141 
Cane sugar, 166 
Caoutchouc, 141 
Caramel, 165 
Carat fine, 128 
Carbamide, 170, 188 
Carbohydrates, 163 
Carbon, 73, 133, 135 

dioxide, 75 

disulphide, 48 

group, 72 

monoxide, 74 
Carbonates, 76 

Carburetted hydrogen, heavy, 139 
Casein, 174, 218 
Caseinogen, 218 
Cast-iron, 113 
Casts, 212 
Catalysis, 34 
Caustic ammonia, 87 

potash, 92 
Cellulin, 163 
Celluloid, 164 
Cellulose, 163 

Centrifuge, 181, 196, 197, 200, 213, 222 
Cerium, 109 
Chalcedony, 81 
Chalk, 98 

Chalybeate water, 29, 116 
Charcoal, 73 

animal, 74 
Chemical action, 9 

affinity, 32 
Chemistry, definition of, 9 

inorganic, 18 

organic, 133 
Chloral, 252 

butylicum, 153 

croton, 153 

hydrate, 152 
Chloralum, 108 
Chloric ether, 150 
Chloride of gold, 29 

of lime, 99 
Chlorides in urine, 196 
Chlorides, test for, 43, 196 



234 



INDEX. 



Chlorinated lime, 99 
Chlorophyl, 77 
Chlorine, 37, 99, 136 

group, 37 

oxides, 41 

oxysalts, 43 

water, 38 
Chloroform, 142 
Choke-damp, 75 
Chromates, no 
Chrome-yellow, 85 
Chromic, oxide, no 

salts, in 
Chromium, no 

trioxide. no 
Chyluri.i, 182, 210 
Cider, 147 

Cinchona alkaloids, 179 
Cinchonicine, 179 
Cinchonidine, 179 
Cinchonine, 179 
Cinnabar, 124 
Citrine ointment, 122 
Clabber, 220 

Classification of elements, 18 
Clay, 81, 109 
Coal, 73 

mineral, 73 
Coal-tar camphor, 142 
Cobalt, 117 
Cocaine, 179 
Codeine, 179 
Colchicine, 179 
Cold, production of, 14, 76 
Coline, 177 
Collodion, 164 

flexible, 164 

styptic, 164 
Colocynthin, 169 
Cologne, 140 

Coloring matters, urinary, 183, 194 
Colostrum, 216 
Columbium, 52 
Combining weight, 16 
Combustible, 22 
Combustion, 22 

supporter of, 22 
Compounds, 14 
Concentrated lye, 91 
Conine, 179 
Copal, 141 
Copper, 118 

ammonio-sulphate, 66 

arsenite, 66 

black oxide, 119 

group, 118 

suboxide, 120 
Copperas, 114 
Corals, 89 
Corundum, 108 
Corrosive sublimate, 123 
Cotton, 163 
Cow's milk, 219 
Crab Orchard salts, 102 
Cream, 222 

of tartar, 92 
Creamometer, 222 
Creasote, 160 



Creatine, 178, 192 
Creatinine, 178, 192 
Cresol, 161 
Creta preparata, 98 
Croton chloral, 153 
Crystallin, 174 
Crystallization, water of, 27 
Cupric hydrate, 119 

oxide, 119 

subacetate, 120 

sulphate, 119 
CuprOus oxide, 120 
Curding, 155 
Cyanates, 80 
Cyanide, mercuric, 79 
Cyanides, compound, 80 
Cyanogen, 79 
Cymogene, 138 
Cystin, 208 

Davy's method, 190 
Decantation, 98 
Decay, 229 
Decone, 140 
Deliquescence, 27 
Deodorizers, 54 
Destructive distillation, 26 
Developer, 128 
Dewar, 20 
Dew-point, 54 
Dextrin, 165 
Diabetic sugar, 167, 201 

urine, 201 
Dialyzed iron, 116 
Dialyzer, 116 
Diamond, 73 
Diastase, 229 
Diethylamine, 178 
Diffusion, 78 

gases, 78 
Digitalin, 169 
Disinfectants, 54 
Distillation, 30 

destructive, 26 

fractional, 30 
Donne's test, 209 
Donovan's solution, 64 
Doremus' method, 191 
Draught in ventilation, 78 
Drummond light, 20 
Dynamite, 159 

Earthenware, 109 
Earths, metals of the, 106 
Earthy phosphates, 182, 195 
Efflorescence, 27 
Elastica, 141 
Elaterin, 168 
Electrolysis, 26, 32 
Electro-positive and negative, 32 
Elements, 14 

classification of, 18 

cable of, 15 
Empirical formulae, 137 
Emplastrum plumbi, 83 
Emery, 108 
Emulsin, 168 
Epithelial casts, 211 



INDEX. 



235 



Epithelium, 210 

Epsom salts, 102 

Equation, 17 

Erbium, 106 

Esbach's albuminometer, 199 

Eserine, 179 

Essence of pear, 148 

artificial, 148 
Essential oils, 140 
Estimation of free HC1, 228 
Etching, 42 
Ethane, 139 
Ethene, 139 

alcohol, 157 
Ethine, 139 
Ether, 149 

butyric, 219 

chloric, 150 

ethyl, 149 

hydrobromic, 151 

hydrochloric, 150 

nitrous, 151 

ozonized, 31 

sulphuric, 149 
Ethers, compound, 145, 149 

mixed, 149 

simple, 145, 149 
Ethyl, alcohol, 146 

aldehyde, 152 

bromide, 151 

chloride, 150 

hydrate, 144 

mercaptan, 149 

nitrite, 151 

oxide, 149 
Ethylamine, 178 
Eudiometer, 26 
Evaporation, 14 
Extraneous bodies in urine, 215 

Fat, 219 

in urine, 210 
Fats, 155 
Fatty casts, 212 
Fehling's test, 202 

solution, 202 
Feldspar, 109 
Ferments, 229 
Ferri citras, 117 

carbonas saccharatus, 116 

et ammonii citras, 117 

et ammonii tartras, 117 

et potassii tartras, 117 

et quininae citras, 117 

et strychniae citras, 117 

pyrophosphas, 117 
Ferric chloride, 114 

hydrate, 115 

nitrate, 116 

sulphate, 114 
Ferricyanides, 80 
Ferricyanogen. 80 
Ferrocyanogen, 80 
Ferrous chloride, 114 

carbonate, 116 

hydrate, 115 

iodide, 116 

sulphate, 114 



Ferrous sulphide, 116 
Ferrum redactum, 113 
Fibrin, 175 
Fibrinogen, 174, 175 
Fibrinoplastin, 175 
Filtration, 98 
Fire-damp, 139 
Fixed oils, 154 
Flashing point, 138 
Flint, 81 

Flowers of sulphur, 45 
Fluid, definition of, 14 
Fluorides, tests for, 45 
Fluorine, 37 
Fluorspar, 38 
Flystone, 117 
Formaldehyde, 152 
Formulas, 17, 137 

molecular, 136 
Fowlers method for urea, 191 

solution, 65 
Fractional distillation, 30 
Fruit essences, artificial, 148 
Fungi, 182 
Fusel oil, 148 

Galena, 82 
Galls, oak, 161 
Galvanized iron, 104 
Gas, definition of, 13 

illuminating, 75, 139 

laughing, 58 

marsh, 139 

natural, 139 
Gasoline, 138 
Gastric juice, 225 

composition of, 225 
Gentianin, 169 
German silver, 117 
Germicides, 54 
Giant powder, 159 
Glass, 81 
Glauber's salt, 90 
Globulin, 173, 200 
Glucose, 167. 201 
Glucosides, 168 
Ghitin, 175 
Gtycerine, 159 
Glvcerites, 159 
Glycerol, 159 
Glyceryl, 158 
Glycol, 157 
Glycyrrhizin, 169 
Glyceryl alcohol, 159 
Glycogen, 166 
Gold cures. 129 

leaf, 128 
Goulard's extract, 84 
Gout, 192 
Granite, 109 
Grape sugar, 167. 201 
Graphite, 73 
Gravity, specific, 10 
Gray powder, 121 
Greek numerals, 41 
Green fire, 101 
Green vitriol, 114 
Groups of the elements, 18 



236 



INDEX. 



Guaiacol, 160 

carbonate, 160 
Gum-resins, 141 
Gums, 164 
Gun cotton, 163 
Gun powder, 94 
Gunzburg's reagent, 227 
Guttapercha, 141 
Gypsum, 99 

Hsematuria, 208 
Haines' test, 202 
Hair dye, 127 
Hartshorn, 55 

spirits of, 55 
Heavy carburetted hydrogen, 139 
Helium, 55 
Heteroxanthine, 178 
Holt, Dr. L. Emmet, 224 
Homatropine, 179 
Homologous series, 134 
Howe's method, 198 
Hydracids, 40 
Hydrates, 26 
Hydrargyri, 

chloridum mite, 123 

iodidum flavum, 122 

iodidum rubrum, 122 

viride, 122 

oxidum flavum, 124 

oxidum rubrum, 124 

subsulphas flavus, 123 
Hydrargyrum, 121 

cum creta, 121 
Hydrobromic ether, 157 
Hydrocarbons, 137 
Hydrochloric ether, 150 
Hydrogen, 19 

antimonide, 69 

arsenide, 64 

carburetted, 139 

cyanide, 79 

dioxide, 30 

monoxide, 25 

-oxide, 25 

peroxide, 30, 208 

sulphide, 46 
Hydroxybenzene, 159 
Hyoscyamine, 179 
Hydrometer, n 
Hyoscine, 179 
" Hypo-," 36 

Hyposulphite of sodium, 49 
Hyposulphites, 49 
Hypoxanthine, 178 

" ic," 41 
Ice, 25 
" ide," 36 

Ignis fatuus, 61 
Illuminating gas, 75 
Indestructibility, 10 
India rubber, 141 
Indican, 169, 194 
Indicators, 97 
Indol, 169 
Ink, 169 

black, 116 



Ink, indelible, 127 

sympathetic, 117 
Inorganic chemistry, 18 
Insolubility, influence of, 33 
Iodide of nitrogen, 53 

of starch, 39, 163 
Iodides, test for, 43 
Iodine, 37, 136 
Iodoform, 144 
Iridium, 129 
Ironj 112 

age, ir8 

by hydrogen, 113 

cast, 113 

dialyzed, 116 

galvanized, 104 

group, no 

Pig,, it 3 

pyrites, 116 

Quevenne's, 113 

reduced, 113 

salts (see Ferrous and Ferric), 
114 

scale, compounds of, 116 

specific gravity of, 12 

wrought, 118 
Isoamylamine, 177 
Isologous series, 134 
Isomerism, 137 
"ite," 3 6 

Jalapin, 169 
Javelle water, 95 

Kalium, 90 
Kaolin, 109 
Kerosene, 138 
Ketone, 145 
Kolbe, 133 
Konig, 218 
Kreatine, 178, 192 
Kreatinine, 178, 192 
Krypton, 55 
Kumyss, 224 

Labarraque's solution, 95 
Lac sulphuris, 45 
Lactometer, n 
Lactoscope, 222 
Lactose, 219 
Lsevulose, 168 
Lamp black, 74^ 
Lana philosophica, 104 
Lanthanum, 106 
Laughing gas, 58 
Lardacein, 175 
Larrabee, 27 
Leachins:, 94 
Lead, 82 

acetate, 83 

carbonate, 84 

chloride, 84 

chromate, 85 

dioxide, 83 

iodide, 85 

nitrate, 83 

oxide, 83 

plaster, 83, 155 



INDEX. 



237 



Lead, puce, 83 

red, 83 

subacetate, 84 

sugar of, 83 

sulphate, 84 

sulphide, 85 

water, 84 

white, 84 
Ledoyen's disinfectant fluid, 83 
Leffmann, 187 
Legumin, 174 
Leucin, 208 
LeucomaVnes, 178 
Licorice, 169 
Lieben's test, 205 
Lignin, 163 
Lime (see Calcium) , 98 

chlorinated, 99 

kilns, 98 

quick, 98 

slaked, 99 

water, 99 
Limestone, 98 

magnesian, 102 
Linen, 163 
Linseed oil, 155 
Liquid, definition of, 13 
Liquor, 26, 87 

acidi arsenosi, 65 

arseni et hydrargyri iodidi, 64 

calcis. 99 

saccharatus, 99 

definition of, 26 

ferri chloridi, 114 
nitratis, 116 
subsulpl atis, 115 
tersulphatis, 115 

gutta-perchae, 141 

hydrargyri nitratis, 122 

iodi compositus, 39 

magnesii citratis, 103 

plumbi subacetatis. 84 

potassae, 93 

potassii arsenitis, 65 
Liter flask, 97 
Litharge, 83 
Lithium, 86 

urate, 86 
Litmus, 40, 88 
Lixiviation, 94 
Lotio nigra, 124 
Lubricating oil, 138 
Lugol's solution, 39 
Lunar caustic, 126 
Lustre, metallic, 82 
Lyddite, 162 
Lye, 91 

Magnesia, 103 

calcined, 103 

milk of, 103 
Magnesian fluid, 196 

limestone, 102 
Magnesium, 102 

carbonate, 103 

citrate, 103 

group, 102 

hydrate, 103 



Magnesium oxide, 103 

phosphate, 103 

sulphate, 102 
Malt, 229 
Maltin, 229 
Maltose, 167 
Manganates, 112 
Manganese, n 1 

black oxide of, 21, 38, in 

chloride, in 

dioxide, 21, 38,111 
Manganous sulphate, 111 

sulphide, 112 
Marble, 98 
Marsh gas, 139 
Marsh's test, 68 
Massa hydrargyri, 121 
Mastic, 141 
Matter, 10 

states of, 13 
Measures, 230 
Meerschaum, 102 
Menthol, 141 
Mercaptans, 148 
Mercurial ointment. 121 
Mercuric ammonium chloride, 123 

chloride, 123 

cyanide, 79 

iodide, 122 

nitrate, 122 

oxide, 124. 

suiphate, 122 

sulphide, 124 
Mercurous chloride, 123 

iodide, 122 

nitrate, 122 

oxide. 124 

sulphate, 122 

sulphide, 124 
Mercury, 121 

acid nitrate, 122 

ammoniated, 123 

bichloride, 123 

biniodide, 122 

black oxide, 124 

green iodide, 122 

mild chloride, 123 

oleate, 124 

proto-iodide, 122 

red iodide, 122 

red oxide, 124 

yellow iodide, 122 

yellow oxide, 124 
" Meta," 62 
Metalbumin, 173 
Metallic lustre, 82 
Metals, 18, 81 
Methane, 138, 139 
Methene, 157 
Methenyl, 158 
Methyl alcohol, 145 

aldehyde, 152 

amine, 178 
Methylated spirit, 146 
Metric measures, 230 
Micrococci, 214 
Micrococcus urea, 185 
Mircro'iganisms, 213 



2 3 8 



INDEX. 



Milk, 216 

adulteration of, 220 

composition of, 217 

cow's, 218 

of magnesia, 103 

of sulphur, 45 

pasteurization of, 220 

salts, 220 

skim, 221 

sterilized, 220 

sugar, 166. 219 

testing, 221 

woman's, 218 
Millon's reagent, 173 
Mineral coal, 73 

sperm oil, 138 
Mirbane, oil of, 142 
Mirrors, 121 
Molecular formulae, 136 
Molecules, 16 
Molybdenum, 117 
Monobromated camphor, 141 
Monsel's solution, 115 
Mordants, 108 
Morphine, 179 

" Mother of vinegar," 154, 229 
Mucilage of starch, 163 
Mucin, 201 
Mucor mucedo, 229 
Mucus, 182, 200 
Mulberry calculus, 205 
Murexid test, 194 
Muscarine, 177 
Mushroom, 177 
Mustard, 169 

Mycoderma aceti, 154, 229 
Mydine, 178 
Myosin, 174 
Myronic acid, 169 
Myrosin, 169 
Myrrh, 141 

Naphtha, 138 
Naphthalene, 142 
Narceine, 179 
Narcotine, 179 
Nascent state, 133 
Natrium, 89 
Natural gas, 139 
Negative radicals, 132 
Neon, 55 

Nessler's reagent, 57, 89 
Neuridine, 178 
Neurin, 177 
Nickel, 117 
Nicotine, 179 
Nitre, 93 

sweet spirits of, 151 
Nitrates, 60 
Nitration, 60 
Nitric oxide, 58 
Nitrification, 58 
Nitrite of amyl, 151 

pentyl, 151 
Nitrites, 58 
Nitro-aniline, 170 
Nitrobenzene, 142 
Nitro-cellulose, 163 



Nitrogen, 52, 135 

dioxide, 58 

group, 52 

hydride, 55 

iodide of, 53 

monoxide, 58 

oxides, 57 

pentoxide, 59 

tetroxide, 59 

trioxide, 58 
Nitro-'glycerine, 159 
Nitrous ether, 151 

oxide, 58 
Nomenclature, 36 
Non-metals, 18 
Normal salts, 91 
Nux vomica alkaloids, 179 

Oi'dium aldicans, 229 
Oil, fusel, 148 

linseed, 155 

of mirbane, 142 

of peppermint, 141 

of vitriol, 50 
Oleate of mercury, 124 
*' Olefines," 139 
Olein, 155 
Oleomargarine, 155 
Oleo-resins, 141 
Oleum terebinthtnae, 140 
Oliguria, 182 
Oils, essential, 140 

fixed, 154 

volatile, 140 
Onyx, 81 

Opium alkaloids, 179 
Organic acids, 153 

alkalies, 175 

chemistry, 133 
Organized bodies, 133 
Orpiment, 64 
" Ortho-," 62 
Orthosilicic acid, 81 
Osmic acid, 129 
Osmium, 129 
" ous," 41 
Oxacids, 40 

Oxalate ot lime, 99, 205 
Oxidation, 22 
Oxide, definition of, 22 
Oxidizing agents, 23 
Oxyacetate, 120 
Oxychloride of antimony, 70 
Oxygen, 21 
Oxygenated water, 30 
Oxy hydrogen flame, 20 
Oxysulphate, 123 
Ozone, 23 

test for, 24 
Ozonized ether, 31 

Painter's colic, 85 
Palladium, 129 
Pancreatin, 229 
Paper, 162 
Paraffine, 138 
Paralbumin, 173 
Paraldehyde, 152 



I\DEX. 



239 



Paraxanthine, 178 
Parchment, artificial, 163 
Parenthesis, 17 
Paris green, 66, 120 
Pasteurization, 221 
Pavy's solution, 202 
Pearl ash, 91 

white, 71, 105 
Pentyl acetate, 148 

nitrite, 151 
Peppermint, oil of, 141 
Pepsin, 225, 229 
Peptones, 175, 200, 225 
" Per-, ' 36 
Permanganates, 112 
Peroxide of sodium, 90 
Perspiration, 141 
Petrolatum, 138 

liquidum, 139 

molle, 139 

spissum, 139 
Petroleum, 138 
Pewter, 71, 83 
Phenates, 159 
Phenacetine, 171 
Phenol, 159 
Phenolphthalein, 97 
Phenyl alcohcl, 159 

bi-sulphate, 160 
Phenylamine, 170 
Phloroglucin, 227 
Phosphates in urine, 195, 182 
Phosphine, 61 
Phosphites, 63 
Phosphoretted hydrogen, 61 
Phosphorus. 60, 136 

hydride, 61 

oxides and oxacids, 62 

pentoxide, 62 

red, 60 

sun, 22 
Phospho-tungstic acid, 200 
Photography, 127 
Picric acid, 161, 203 

test for glucose, 203 
Physostigmine, 179 
Pig iron, 113 
Pilocarpine, 179 
Pilula hydrargyri, 121 
Pipette, 97 

14 ?laster-of-Paris," 99 
Plasters, 155 
Platinic chloride, 89, 129 
Platinum, 129 
Plumbago, 73 
Plumbum, 82 
Polymerism, 137 
Polyuria, 181 
Porcelain, 109 
Porter, 147 
Potassium, 90 

acid carbonate, 92 

bicarbonate, 92 

bichromate, in 

bitartrate, 92 

bromide, 93 

carbcnate, 91 

chlorate, 21 



Potassium chromate, in 

ferricyanide, 80 

ferrocyanide, 80 

group. 86 

hydrate, 94 

hypochlorite, 94 

iodate, 93 

iodide, 93 

manganate, 112 

nitrate, 93 

per nanganate, 112 

red chromate, n 1 

-sodium tartrate, 94 

sulphocyanate, 80, 224 
Potato starch, 165 
Pottery, 109 
Powder of Algaroth, 70 
Precedence of affinities, 73 
Precipitated chalk, 93 
Preliminary group, 19 
Propane, 137 
Propenyl, 158 
Propyl, 144 
Propylamine, 169 
Proteids, 172, 178 
Proto-iodide of mercury, 122 
Prussiate of potash, red, 80 

yellow, 80 
Pseudoxanthine, 178 
Ptomaines, 176 
Ptyalin, 125, 229 
Ptyalism, 125 
Purple of Cassius, 129 
Pus in urine, 209 

test for, 31, 209 
Putrefaction, 229 
Putrefactive alkaloids, 176 
Putrescine, 178 
Pyocyanine, 178 
" Pyro-", 62 
Pyroligneous spirit, 145 
Pyrozone, 23 
Pyuria, 209 

Quartz, 81 

Quevenne's iron, 113 
Quicklime, 98 
Quicksilver, 121 
Quimcine, 179 
Quinidine, 179 
Quinine. 179 
Quinoidine, 179 

Radicals, definition of, 31 

the alcohol, 144 
Ramsay, Prof., 55 
Rancidity of fats, 155 
Rational formulae, 137 
Ratsbane, 64 
Rayleigh, Lord, 55 
Realgar, 64 
Red fire, 101 

prussiate of potash, 80 
Reduced iron, 113 
Rennet, 219 
Reinsch's test, 123 
Resina, 141 
Resins, 140 



240 



INDEX. 



Resorcin, 160 
Respiration, 23 
Rhigoline, 138 
Rochelle salt, 94 
Rock crystal, 81 

salt, 90 
Roll sulphur, 44 
Rosaniline, 170 
Rosin (see Resin), 140 
Rubber, India, 141 

vulcanized, 141 
Rubidium, 96 

Saccharin, 161 

Saccharomyces cerevisiae, 229 
Saccharum, 166 
Saccharoses, 166 
Salamandarine, 178 
Salicin, 168 
Saliva, 224 
Salt-peter, 93 
Salts, acid, 91 

"bi-," 9x 

Crab-orchard, 102 

Epsom, 102 

normal, 91 

of tartar, 91 
Salivation, 125 
Salol, 161 
Salophen, 161 
Salt, common, 
Sal-volatile, 88 
Samarium, 106 
Sand, 81 

specific gravity of, 13 
Santonin, 169 
Saponification, 157 
Saponin, 169 
Sapphire, 108 
Sarcina, 214 

Scale compounds of iron, ri6 
Scandium, 106 
Scheele's green, 66, 120 
Secretion of urine, 180 
Selenium, 44 
Serum-therapy, 179 
Sewer gas, 46 
Shellac, 141 

Siemen's ozone tube, 23 
Silica. 81 
Silicates, 81 
Silicic oxide, 81 
Silicon, 81 
Silver, 126 

action of light on, 127 

ammonio-nitrate, 66 

arsenite, 66 

bromide, 127 

chloride, 127 

cyanide, 127 

German, 117 

iodide, 127 

nitrate, 126 

oxide, 126 
Slaked lime, 99 
Soaps, 155^ 
Soap solution, 100 
Soapstone, 81, 152 



Soda, baking, 90 

water, 77 
Sodio-potassium tartrate, 94 
Sodium, 89 

amalgam, 87 

bicarbonate, 90 

borate, 107 

chloride, 89 

dioxide, 90 

hypobromite, 191 

hyposulphite, 49 

phosphate, 90 

salicylate, 161 

sulphate, 90 

sulphite, 90 

sulphocarbolate, 

thiosulphate, 49 

tungstate, 118 
Solder, 83 
Soldering, 107 
Solid, definition of, 13 
Solanin, 169 

Solomon, Dr. Leon L., 101 
Soluble glass, 81 
Solution, Donovan's, 64 

Labarraque's, 95 
Solution, rationale of, 26 
Soot, 74 

Spasmotoxine, 177 
Specific gravity, 16, 186 

flask, 11 

weight, 16 
Spectroscope, 209 
Spermatozoa, 213 
Spermine, 178 
Spirit, methylated, 146 

pyroligneous, 145 

wood, 145 
Spirits, 87, 147 

of hartshorn, 55 

of wine, 146 
Spiritus setheris nitrosi, 151 

ammonise, 87 

ammoniae aromaticus, 87 

frumenti, 147 

vini gallici, 147 
Squibb's, 187, 191 
Stannic salts, 82 
Stannous salts, 82 
Stannum, 82 
Starch, 164 
Steam, 25 
Steel, 113 

Stereotyping metal, 71 
Sterilized milk, 220 
Stibine, 69 
Stibium, 69 
Stomach contents, 226 
Strontium, 101 
Strychnine, 179 
Styptic collodion, 164 
Sublimation, 30 
Sublimed sulphur, 44 
Suboxide of copper, 120 
Sugar, beet, 166, 201 

cane, 166 

corn, 168 

diabetic, 167 



IXDEX. 



2 4 1 



Sugar, grape, 167 

in urine, 201 

milk, 166, 219 

of lead, 83 

specific gravity of, 13 
Sulphates, test for, 51, 197 
Sulphites, 49 
Sulphocarbolates, 160 
Sulpho-cyanates, 80 
Sulphonal, 149 

Sulph-indigotate of sodium, 18c 
Sulphur, 44, 45, 135 

dioxide, 49 

flowers of, 45 

group, 44 

lotum, 45 

milk of, 45 

oxides, 48 

precipitatum, 45 

sublimatum, 45 

trioxide, 49 
Sulphuretted hydrogen^ 46 
Sulphuric ether, 149 
Supporter of combustion, 22 
Susotoxine, 177 
Sweet spirits of nitre, 151 
Symbols, 17 
Sympathetic ink, 117 
Synaptase, 168 
Synthesis, 26 
Syntonin, 174 

Syrupus calcii lactophosphatis, 99 
Syrupus scillse compositus, 70 

simplex, t66 

Table, 

of alkaloids, 179 

of elements, 15 

of metric measures, 230 

of solubilities, 132 

to determine acidulous radicals, 131 

to determine metallic radicals, 130 

of valences, 35 
Tannin, 169 
Tanning, 169 
Tantalum, 52 
Tartar, cream of, 92 

emetic, 70 
Teeth, filling for, 105 
Tellurium, 44 

Temperature, influence of, 33 
Terebene, 140 
Terpenes, 140 
Tersulphate of iron, 114 
Test-meal, 225 
Tests, 

alcohol, 147 

alkali-bismuth, 203 

alkoli-copper, 202 

ammonia, 57 

ammonium salts, 88, 89 

antimony, 71 

arsenic, 67, 68 

barium, 197 

bile acids, 207 

bile coloring matters, 206 

bismuth, 72 

biuret, 172 



Tests, 

blood, 209 

boron, 107 

bromides. 43 

bromine, 40 

brucine, 179 

cadmium, 106 

calcium, 100 

carbonates, 78 

carbon dioxide, 78 

carbonic acid, 78 

chlorides, 43, 196 

chlorine, 40 

chloroform, 143 

chromates, 84 

cobalt, 117 

coloring matters, urinary, 194 

Congo-red, 226 

copper, 119 

cyanides, 80 

Donne's, 209 

fats, 154 

Fehling's, 202 

fluorides, 43 

gallic acid, 162 

glucose in urine, 201 

Haines', 202 

hard water, 100 

heat for albumin, 198 

hydrocyanic acid, 80 

hydrogen sulphide, 47 

indigo-carmine, 203 

iodides, 43 

iodoform, 147 

iodine, 40, 165 

iron, 116 

lead, 85 

Lieben's, 205 

lithium, 86 

manganese, 107 

Marsh's, 68, 71 

mercury, 125 

metallic radicals, 130 

morphine, 179 

murexid, 194 

nickel, 117 

nitrates, 60 

nitric acid, 60 

nitrogenous bodies, 135 

organic matter in water, 38 

oxalic acid, 157 

oxygen, 58 

ozone, 24 

phenyl-glucosazone, 204 

phenyl-hydrazine, 203 

phosphates, 63 

phosphoric acid, 63 

phosphorus, 61 

picric acid, 203 

platinic chloride, 94 

potassium, 36 

pus, 31 

pyrogallic acid, 163 

quinine, 179 

Reinsch's, 66 

rennet, 227 

salicylic acid, 162 

silver, 196 



242 



INDEX. 



Tests, 

silver nitrate, 127, 197 

sodium, 90 

starch, 163 

strychnine, 179 

strontium, 101 

sugar, 167, 201 

sulphates, 51, 197 

.sulphuric acid, 51 

tannic acid, 167 

Trommer's, 201 

Uffelman's, 227 

urates, 182, 191, 194 

urea, 188, 190 

uric acid, 194 

urinary calculi, 215 

urinary sediments, 215 

water in alcohol, 119 

zinc, 105 
Tetanine, 176 
Tetanotoxine, 177 
Theine, 179 
Theobromine, 179 
Theory, atomic, 15 
Tin, 82 
Tinct. ferri chloridi, 114 

iodi, 39 
Tinctures, 87, 147 
Tin-foil, 82 
Tin-ware, 82 
Tolu, 141 
Toluene, 142 
Torula cerevisise, 229 
Toxicology of arsenic, 65 
Toxines, 178 
Tetrane, 139 
Trichloraldehyde, 142 
Trichlormethane, 142 
Trimethyl amine, 171, 178 
Triple-phosphates, 195 
Tritane, 139 
Tritenyl, 158 

nitrate, 159 
Tritone, 140 
Trityl, 148 
Trommer's test, 202 
Trypsin, 229 
Tube-casts, 211 
Tungsten, 117 
Turpentine, 140 
Turpeth mineral, 123 
Type-metal, 83 
Typhotoxine, 177 
Tyrotoxicon, 177, 220 
Tyrosin, 208 

Ultimate analysis, 135 
Unguentum antimonii, 70 

hydrargyri, 121 

hydrargyri nitratis, 122 
Uranium, 117 
Urates, 182, 191 
Urea, 80, 170, 179, 181, 188 

estimation of, 189 

nitrate, 188 

quantitative analysis, 190 
Uric acid, 192 
Urinary calculi, 215 



Urinary casts, 211 
Urine, 180 

abnormal, 198 

acid fermentation, 185 

acidity, 184 

alkaline fermentation, 185 

chemical constituents, 188 

color, 183 

coloring matters, 183, 194 

fluidity, 183 

mucus, 182 

normal, 181 

odor, 183 

opacity, 182 

physical properties, 181 

quantity, 181 

reaction, 183 

specific gravity, 186 

transparency, 182 
Urinometer, n, 186 
Urobilin, 194 
Urohaematin, 194 
Uroindican, 194 
Uroxanthin, 194 

Valence, 34 

table of, 35 
Valerian, 154 
Vanadium, 52 
Vanillin, 227 
Vapor, 25 

Vapor-densities, 136 
Varnishes, 141 
Vaseline, 139 
Veratrine, 179 
Ventilation, 78 
Verdigris, 120 
Vermilion, 124 
Vibriones, 215 
Vinegar, 154 

" mother of," 154, 230 
Vinum antimonii, 70 
Vinum rubrum, 147 
Vitellin, 174 
Vitriol, blue, 119 

green, 114 

oil of, 50 

white, 104 
Volatile oils, 140 
Volatility, influence of, 33 
Vulcanized rubber, 141 
Volumetric solutions, 96 

Water, 25 

alkaline, 29 
analysis, 28 
chalybeate, 29 
carbonated, 28 
distilled, 30 
drinkable, 27 
filtration, 29 
glass, 81 
hard, 100 

impure, tests for, 28 
mineral, 28 
natural, 27 
lithia, 29 
of crystallization, 27 



INDEX. 



243 



Water, oxygenated, 30 

potable, 27 

purification of, 29 

saline, 29 

sulphur, 29 

thermal, 2,) 
Waxy casts, 212 
Weight, 10 

absolute, 10 

apparent, 10 

atomic, 16 

combining, 16 

specific, 10 
Welding, 107 
Wells, 27 

Welsbach burner, 109 
Werner-Schmidt process, 223 
Whey, 219 
Whiskey, 147 
W T hite arsenic, 64 

lead, 84 

precipitate, 123 

vitriol, 104 
" Will-o' the wisp," 61 
Wines, 147 
Woehler, 133 



Woman's milk, 218 
Wood alcohol, 145 

naphtha, 145 

spirit, 145 
Woody fibre, 163 
Wrought iron, 113 

Xanthine, 178, 192 
Xanthoproteic, 172 

Yeast, 146, 201, 213, 229 

Yellow, chrome, 85 

iodide of mercury, 122 
prussiate of potash, 80 

Ytterbium, 106 

Yttrium, 106 

Zinc, 104 

carbonate, 105 

chloride, 104 

oxide, 105 

sulphate, 104 

sulphide, 105 

white, 105 
Zoogleae. 215 



NO. 8 APRIL, 1900 

A Classified Catalogue of 
Books on Medicine and the 
Collateral Sciences, Phar- 
macy, Dentistry, Chemistry, 
Hygiene, Microscopy, Etc. 



e^ 



P. Blakiston's Son & Company, Pub- 
lishers of Medical and Scientific Books, 
1012 Walnut Street, Philadelphia 



SUBJECT INDEX. 



Special Catalogues of Books on Pharmacy, Dentistry, 
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SUBJECT. PAGE 

Alimentary Canal (see Surgery) 19 

Anatomy 3 

Anesthetics 14 

Autopsies (see Pathology) 16 

Bacteriology (see Pathology).. 16 

Bandaging (see Surgery) 19 

Blood, Examination of 16 

Brain 4 

Chemistry 4 

Children, Diseases of 6 

Climatology 14 

Clinical Charts 6 

Compends 22, 23 

Consumption (see Lungs) n 

Cyclopedia of Medicine 8 

Dentistry 7 

Diabetes (see Urin. Organs).. 21 

Diagnosis 17 

Diagrams (see Anatomy) 3 

Dictionaries 8 

Diet and Food 14 

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Life Insurance 14 

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Materia Medica 12 

Medical Jurisprudence 13 

Microscopy 13 

Milk Analysis (see Chemistry) 4 



SUBJECT. PAGE 

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Nose 20 

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Obstetrics 16 

Ophthalmology 9 

Organotherapy 14 

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Pharmacy 16 

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DICTIONARIES. 

GOULD. The Illustrated Dictionary of Medicine, Biology, 
and Allied Sciences. Being an Exhaustive Lexicon of Medicine 
and those Sciences Collateral to it: Biology (Zoology and Botany), 
Chemistry, Dentistry, Parmacology, Microscopy, etc., with many 
useful Tables and numerous fine Illustrations. 1633 pages. 5th Ed. 
Sheep or Half Dark Green Leather, $10.00; Thumb Index, $11.00 
Half Russia, Thumb Index, $12.00 

GOULD. The Medical Student's Dictionary. Including all the 
Words and Phrases Generally Used in Medicine, with their Proper 
Pronunciation and Definition, Based on Recent Medical Literature. 
With Tables of the Bacilli, Micrococci, Mineral Springs, etc., of the 
Arteries, Muscles, Nerves, Ganglia, and Plexuses, etc. 10th Edition. 
Rewritten and Enlarged. Completely reset from new type. 700 pp. 
Half Dark Leather, $3.25 ; Half Morocco, Thumb Index, $4.00 

GOULD. The Pocket Pronouncing Medical Lexicon. 4th Edi- 
tion. (30,000 Medical Words Pronounced and Defined.) Containing 
all the Words, their Definition and Pronunciation, that the Medical, 
Dental, or Pharmaceutical Student Generally Comes in Contact 
With; also Elaborate Tables of the Arteries, Muscles, Nerves, 
Bacilli, etc., etc., a Dose List in both English and Metric Systems, 
etc., Arranged in a Most Convenient Korm for Reference and Memor- 
izing. A new (Fourth) Edition, Revised and Enlarged. 838 
pages. Just Ready. 

Full Limp Leather, Gilt Edges, $1.00; Thumb Index, $1.25 

100,000 Copies of Gould's Dictionaries Have Been Sold. 

GOULD AND PYLE. Cyclopedia of Practical Medicine and 
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One Volume. A Concise Reference Handbook, Alphabetically 
Arranged, of Medicine, Surgery, Obstetrics, Materia Medica, 
Therapeutics, and the Various Specialties, with Particular Reference 
to Diagnosis and Treatment. Compiled under the Editorial Super- 
vision of George M. Gould, m.d., Author of "An Illustrated 
Dictionary of Medicine" • Editor " Philadelphia Medical Journal," 
etc.; and Walter L. Pyle, m.d., Assistant Surgeon Wills Eye 
Hospital ; formerly Editor " International Medical Magazine," etc., 
and Seventy-two Special Contributors. With many Illustrations. 
Large Square Octavo, to correspond with Gould's " Illustrated 
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*** Sample Pages and Illustrations and Descriptive Circulars of 

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MAXWELL, Terminologia Medica Polyglotta. By Dr. 
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The object of this work is to assist the medical men of any nationality 

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Each term is usually given in seven languages, viz. : English, French, 

German, Italian, Spanish, Russian, and Latin. 

TREVES AND LANG. German-English Medical Dictionary. 

Half Russia, $3.25 



MEDICAL BOOKS. 9 

EAR (see also Throat and Nose). 

BURNETT. Hearing and How to Keep It. Illustrated. .40 

DALBY. Diseases and Injuries of the Bar. 4th Edition. 38 
Wood Engravings and 8 Colored Plates. $2.50 

HOVELL. Diseases of the Ear and Naso-Pharynx. Includ- 
ing Anatomy and Physiology of the Organ, together with the Treat- 
ment of the Affections of the Nose and Pharynx which Conduce to 
Aural Disease. 122 Illustrations. 2d Edition. Preparing. 

PRITCHARD. Diseases of the Ear. 3d Edition, Enlarged. 
Many Illustrations and Formulae. $1.50 

WOAKES. Deafness, Giddiness, and Noises in the Head. 
4th Edition. Illustrated. $2.00 

ELECTRICITY. 

BIGELOW. Plain Talks on Medical Electricity and Bat- 
teries. With a Therapeutic Index and a Glossary. 43 Illustra- 
tions. 2d Edition. #1.00 

HEDLEY. Therapeutic Electricity and Practical Muscle 
Testing. 99 Illustrations. Just Ready. $2.50 

JACOBI. Electrotherapy. Illustrated. In Press. 

JONES. Medical Electricity. 3d Edition. 112 Illus. In Press. 

MASON. Medical Electricity. Numerous Illustrations. .75 



EYE. 

A Special Circular of Books on the Eye sent free upon application . 

DONDERS. The Nature and Consequences of Anomalies of 
Refraction. With Portrait and Illustrations. Half Morocco, $1.25 

FICK. Diseases of the Eye and Ophthalmoscopy. Trans- 
lated by A. B. Hale, m. d. 157 Illustrations, many of which are in 
colors, and a glossary. Cloth, #4.50 ; Sheep, #5.50 

GOULD AND PYLE. Compend of Diseases of the Eye and 
Refraction. Including Treatment and Operations, and a Section 
on Local Therapeutics. With Formulae, Useful Tables, a Glossary, 
and in Illus., several of which are in colors. 2d Edition, Revised. 

Cloth, .80; Interleaved, $1.25 

GOWERS. Medical Ophthalmoscopy. A Manual and Atlas 
with Colored Autotype and Lithographic Plates and Wood-cuts, 
Comprising Original Illustrations of the Changes of the Eye in Dis- 
eases of the Brain, Kidney, etc. 3d Edition. $4.00 

HARLAN. Eyesight, and How to Care for It. Illus. .40 

HARTRIDGE. Refraction. 104 Illustrations and Test Types. 
10th Edition, Enlarged. Just Ready. #1.50 

HARTRIDGE. On the Ophthalmoscope. 3d Edition. With 
4 Colored Plates and 68 Wood-cuts. $1.50 

HANSELL AND REBER. Muscular Anomalies of the Eye. 
Illustrated. $ I -5o 

HANSELL AND BELL. Clinical Ophthalmology. Colored 
Plate of Normal Fundus and 120 Illustrations. $1.50 

JESSOP. Manual of Ophthalmic Surgery and Medicine. Col- 
ored Plates and 108 other Illustrations. Cloth, $3.00 



10 SUBJECT CATALOGUE. 

MORTON. Refraction of the Eye. Its Diagnosis and the Cor- 
rection of its Errors. 6th Edition. $1.00 

OHLEMANN. Ocular Therapeutics. Authorized Translation, 
and Edited by Dr. Charles A. Oliver. $*-75 

PHILLIPS. Spectacles and Eyeglasses. Their Prescription 
and Adjustment. 2d Edition. 49 Illustrations. $1.00 

SWANZY. Diseases of the Eye and Their Treatment. 6th 

Edition, Revised and Enlarged. 158 Illustrations, 1 Plain Plate, 
and a Zephyr Test Card. $3.00 

THORINGTON. Retinoscopy. 3d Edition. Illustrated. |i.oo 

THORINGTON. Refraction and How to Refract. 200 Illustra- 
tions, 13 of which are Colored. 301 pages. Just Ready. #1.50 

WALKER. Students' Aid in Ophthalmology. Colored Plate 
and 40 other Illustrations and Glossary. $150 

FEVERS. 

COLLIE. On Fevers. Their History, Etiology, Diagnosis, Prog- 
nosis, and Treatment. Colored Plates. $2.00 

GOODALL AND WASHBOURN. Fevers and Their Treat- 
ment. Illustrated. &J.00 

GOUT AND RHEUMATISM. 

DUCKWORTH. A Treatise on Gout. With Chromo-lithographs 
and Engravings. Cloth, $6.00 

GARROD. On Rheumatism. A Treatise on Rheumatism and 
Rheumatic Arthritis. Cloth, $5.00 

HAIG. Causation of Disease by Uric Acid. A Contribution to 
the Pathology of High Arterial Tension, Headache, Epilepsy, Gout, 
Rheumatism, Diabetes, Bright* s Disease, etc. 4th Edition. $3.00 

HEART. 

SANSOM. Diseases of the Heart. The Diagnosis and Pathology 
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Illustrations. $6.00 

THORNE. The Schott Methods of the Treatment of Chronic 
Heart Disease. Third Edition. Illustrated. Just Ready. $1 75 

HISTOLOGY. 

STIRLING. Outlines of Practical Histology. 368 Illustrations 
2d Edition, Revised and Enlarged. With new Illustrations. #2.00 

STOHR. Histology and Microscopical Anatomy. Translated 
and Edited by A. Schaper, m.d.. Harvard Medical School. Second 
American from 7th German Edition, Revised and Enlarged. 292 
Illustrations. $3.00 



MEDICAL BOOKS. 11 



HYGIENE AND WATER ANALYSIS. 

Special Catalogue of Books on Hygiene sent free upon application. 

CANFIELD. Hygiene of the Sick-Room. A Book for Nurses 
and Others. Being a Brief Consideration of Asepsis, Antisepsis, Dis- 
infection, Bacteriology, Immunity, Heating, Ventilation, etc. $1.25 

COPLIN. Practical Hygiene. A Complete American Text-Book. 
138 Illustrations. New Edition. Preparing . 

ERNST. Prophylaxis and Personal Hygiene. In Press. 

HARTSHORNE. Our Homes. Illustrated. .40 

KENWOOD. Public Health Laboratory Work. 116 Illustra- 
tions and 3 Plates. $2.00 

LEFFMANN. Examination of Water for Sanitary and 
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LEFFMANN. Analysis of Milk and Milk Products. Illus- 
trated. Second Edition. $1.25 

LINCOLN. School and Industrial Hygiene. .40 

MACDONALD. Microscopical Examinations of Water and 
Air. 25 Lithographic Plates, Reference Tables, etc. 2d Ed. $2.50 

McNEILL. The Prevention of Epidemics and the Construc- 
tion and Management of Isolation Hospitals. Numerous Plans 
and Illustrations. $3«5o 

NOTTER AND FIRTH. The Theory and Practice of Hygiene. 
10 Plates and 135 other Illustrations. 1034 pages. 8vo. $7-oo 

PARKES. Hygiene and Public Health. By Louis C. Parkes, 
m.d. 5th Edition. Enlarged. Illustrated. #2.50 

PARKES. Popular Hygiene. The Elements of Health. A Book 
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STARR. The Hygiene of the Nursery. Including the General 
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Management of the Ordinary Emergencies of Early Life, Massage, 
etc. 6th Edition. 25 Illustrations. $1.00 

STEVENSON AND MURPHY. A Treatise on Hygiene. By 
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*** Each Volume sold separately. Special Circular upon application. 

THRESH. Water and Water Supplies. 2d Edition. $2.00 

WILSON. Hand-Book of Hygiene and Sanitary Science. 
Wiih Illustrations. 8th Edition. $3- 00 

WEYL. Sanitary Relations of the Coal-Tar Colors. Author- 
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LUNGS AND PLEURiE. 

HARRIS AND BEALE. Treatment of Pulmonary Consump- 
tion. $2.50 

KNOPF. Pulmonary Tuberculosis. Its Modern Prophylaxis 
and Treatment in Special Institutions and at Home. Illus. $3.00 

POWELL. Diseases of the Lungs and Pleurae, including 
Consumption. Colored Plates and other Illus. 4th Ed. $4.00 



12 SUBJECT CATALOGUE. 

MASSAGE. 

KLEEN. Hand-Book of Massage. Authorized translation by 
Mussey Hartwell, m.d., ph.d. With an Introduction by Dr. S. 
Weir Mitchell. Illustrated by a series of Photographs Made 
Especially by Dr. Kleen for the American Edition. $2.25 

OSTROM. Massage and the Original Swedish Move- 
ments. Their Application to Various Diseases of the Body. A 
Manual for Students, Nurses, and Physicians. Fourth Edition, En- 
larged. 105 Illustrations, many of which are original. $1.00 

MITCHELL AND GULICK. Mechanotherapy. Illus. In Press. 

WARD. Notes on Massage. Interleaved. Paper cover, $1. 00 



MATERIA MEDICA AND THERA- 
PEUTICS. 

BIDDLE. Materia Medica and Therapeutics. Including Dose 
List, Dietary for the Sick, Table of Parasites, and Memoranda of 
New Remedies. 13th Edition, Revised. 64 Illustrations and a 
Clinical Index. Cloth, $4.00 ; Sheep, #5.00 

BRACKEN. Outlines of Materia Medica and Pharmacology. #2.75 

COBLENTZ. The Newer Remedies. Including their Synonyms, 
Sources, Methods of Preparation, Tests, Solubilities, Doses, etc. 
3d Edition, Enlarged and Revised. $1.00 

COHEN. Physiologic Therapeutics. Mechanotherapy, Mental 
Therapeutics, Electrotherapy, Climatology, Hydrotherapy, Pneumo- 
therapy, Prophylaxis, Alimentotherapy, etc. In Press. 

DAVIS. Materia Medica and Prescription Writing. $150 

GOROAS. Dental Medicine. A Manual of Materia Medica and 
Therapeutics. 6th Edition, Revised. $4.00 

GROFF. Materia Medica for Nurses, with questions for Self Exam- 
ination and a complete Glossary. $1-25 

HELLER. Essentials of Materia Medica, Pharmacy, and 
Prescription "Writing. #1.50 

MAYS. Theine in the Treatment of Neuralgia. % bound, .50 

POTTER. Hand-Book of Materia Medica, Pharmacy, and 
Therapeutics, including the Action of Medicines, Special Therapeu- 
tics, Pharmacology, etc., including over 600 Prescriptions and For- 
mulae. 7th Edition, Revised and Enlarged. With Thumb Index in 
each copy. Cloth, $5.00; Sheep, $6. co 

POTTER. Compend of Materia Medica, Therapeutics, and 
Prescription Writing, with Special Reference to the Physiologi- 
cal Action of Drugs. 6th Edition. .80; Interleaved, $1.25 



MEDICAL BOOKS. 13 



SAYRE. Organic Materia Medica and Pharmacognosy. An 

Introduction to the Study of the Vegetable Kingdom and the Vege- 
table and Animal Drugs. Comprising the Botanical and Physical 
Characteristics, Source, Constituents, and Pharmacopeial Prepara- 
tions, Insects Injurious to Drugs, and Pharmacal Botany. With 
sections on Histology and Microtechnique, by W. C. Stevens. 
374 Illustrations, many of which are original. 2d Edition. 

Cloth, $4.50 

WARING. Practical Therapeutics. 4th Edition, Revised and 
Rearranged. Cloth, #2.00; Leather, $3.00 

WHITE AND WILCOX. Materia Medica, Pharmacy, Phar- 
macology, and Therapeutics. 4th American Edition, Revised by 
Reynold W. Wilcox, m.a.. m.d., ll.d., Professor of Clinical 
Medicine and Therapeutics at the New York Post-Graduate Medical 
School. Cloth, $3.00; Leather, $3.50 

" The care with which Dr. Wilcox has performed his work is con- 
spicuous on every page, and it is evident that no recent drug possess- 
ing any merit has escaped his eye. We believe, on the whole, this is 
the best book on Materia Medica and Therapeutics to place in the 
hands of students, and the practitioner will find it a most satisfactory 
work for daily use." — The Cleveland Medical Gazette. 



MEDICAL JURISPRUDENCE AND 
TOXICOLOGY. 

REESE. Medical Jurisprudence and Toxicology. A Text-Book 
for Medical and Legal Practitioners and Students. 5th Edition. 
Revised by Henry Lkffmann, m.d. Clo.,^3.00; Leather, $3.50 

" To the student of medical jurisprudence and toxicology it is in- 
valuable, as it is concise, clear, and thorough in every respect." — The 
American Journal of the Medical Sciences. 

MANN. Forensic Medicine and Toxicology. Illus. $6.50 

TANNER. Memoranda of Poisons. Their Antidotes and Tests. 
7th Edition. .75 



MICROSCOPY. 

CARPENTER. The Microscope and Its Revelations. 8th 
Edition. 800 Illustrations and many Lithographs. Preparing. 

LEE. The Microtomist's Vade Mecum. A Hand-Book of 
Methods of Microscopical Anatomy. 887 Articles. 5th Edition, 
Enlarged. In Press. 

REEVES. Medical Microscopy, including Chapters on Bacteri- 
°l°gy> Neoplasms, Urinary Examination, etc. Numerous Illus- 
trations, some of which are printed in colors. $2.50 

WETHERED. Medical Microscopy. A Guide to the Use of the 
Microscope in Practical Medicine. 100 Illustrations. $2.00 



14 SUBJECT CATALOGUE. 

MISCELLANEOUS. 

BRAMWELL. Anaemia. #2.50 

BURNETT. Foods and Dietaries. A Manual of Clinical Diet- 
etics. 2d Edition. $i-5o 
BUXTON. Anaesthetics. Illustrated. 3d Edition. $1.50 
COHEN. Organotherapy. In Press. 
DAVIS. Alimentotherapy. In Press. 
FEN WICK. Ulcer of the Stomach. 42 Illustrations. #3.50 
GOULD. Borderland Studies. Miscellaneous Addresses and 
Essays. i2mo. $2.00 
GREENE. Medical Examination for Life Insurance. Illus- 
trated. In Press. 
HAIG. Causation of Disease by Uric Acid. A Contribution to 
the Pathology of High Arterial Tension, Headache, Epilepsy, Gout, 
Rheumatism, Diabetes, Bright' s Disease, etc. 4th Edition. $3.00 
HAIG. Diet and Food. Considered in Relation to Strength and 
Power of Endurance. 2d Edition. Just Ready. $1.00 
HEMMETER. Diseases of the Stomach. Their Special Path- 
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etics, Surgery, etc. 2d Edition, Revised and Enlarged. Illustrated. 
Just Ready. Cloth, $6.00; Sheep, $7.00 
HENRY. A Practical Treatise on Anemia. Halt Cloth, .50 
MARSHALL. History of Woman's Medical College of Penn- 
sylvania. $ 1 -5° 
NEW SYDENHAM SOCIETY'S PUBLICATIONS. Circulars 
upon application. Per Annum, $8.00 
OSGOOD. The Winter and Its Dangers. .40 
PACKARD. Sea Air and Sea Bathing. .40 
PARRISH. Alcoholic Inebriety. $1.00 
RICHARDSON. Long Life and How to Reach It. .40 
ST. CLAIR. Medical Latin. $1.00 
TESSIER. Pneumotherapy. In Press. 
TREVES. Physical Education : Its Effects, Methods, Etc. .75 
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WEBER AND HINSDALE. Climatology. In Press. 
WILSON. The Summer and Its Diseases. .40 
WINTERNITZ. Hydrotherapy. In Press. 



NERVOUS DISEASES. 

BEEVOR. Diseases of the Nervous System and their Treat- 
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DERCUM. Rest, Hypmotism, Mental Therapeutics. In Press. 

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GOWERS. Manual of Diseases of the Nervous System. A 
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Vol. I. Diseases of the Nerves and Spinal Cord. 3d Edition, En- 
larged. Cloth, $4.00 ; Sheep, $5.00 
Vol. II. Diseases of the Brain and Cranial Nerves ; General and 
Functional Disease. 2d Edition. Cloth, $4.00; Sheep, $5.00 

GOWERS. Syphilis and the Nervous System. $1.00 

GOWERS. Clinical Lectures. A New Volume of Essays on the 
Diagnosis, Treatment, etc., of Diseases of the Nervous System. $2.00 



MEDICAL BOOKS. 15 



GO WERS. Epilepsy and Other Chronic Convulsive Diseases. 
2d Edition. In Press, 

HORSLEY. The Brain and Spinal Cord. The Structure and 
Functions of. Numerous Illustrations. $2.50 

ORMEROD. Diseases of the Nervous System. 66 Wood En- 
gravings. $1.00 

OSLER. Chorea and Choreiform Affections. $2.00 

PRESTON. Hysteria and Certain Allied Conditions. Their 
Nature and Treatment. Illustrated. $2.00 

WOOD. Brain Work and Overwork. .40 

NURSING (see also Massage). 

Special Catalogue of Books for Nurses sent free upon application. 

BROWN. Elementary Physiology for Nurses. .75 

CANFIELD. Hygiene of the Sick-Room. A Book for Nurses and 
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tion, Bacteriology, Immunity, Heating and Ventilation, and Kindred 
Subjects for the Use of Nurses and Other Intelligent Women. #1.25 

CUFF. Lectures to Nurses on Medicine. New Edition. $1.25 

DOMVILLE. Manual for Nurses and Others Engaged in At- 
tending the Sick. 8th Edition. With Recipes for Sick-room Cook- 
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FULLERTON, Obstetric Nursing. 41 Ills. 5th Ed. gi.oo 

FULLERTON. Surgical Nursing. Comprising the Regular 
Course of Instruction at the Training-School of the Woman's Hos- 
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GROFF. Materia Medica for Nurses. With Questions for Self-Ex- 

amination and a very complete Glossary. $1.25 

" It will undoubtedly prove a valuable aid to the nurse in securing a 

knowledge of drugs and their uses/' — The Medical Record, New 

York. 

HORWITZ. Duties of the Surgical Nurse. In Press. 

HUMPHREY. A Manual for Nurses. Including General 
Anatomy and Physiology, Management of the Sick Room, etc. 
17th Ed. Illustrated. $1.00 

" In the fullest sense, Dr. Humphrey's book is a distinct advance on 
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medicine and surgery for the beginner, incorporating with the text the 
management of childbed and the hygiene of the sick-room, its value 
is greatly enhanced by copious wood -cuts and diagrams of the bones 
and internal organs." — British Medical Jour nal , London. 
STARR. The Hygiene of the Nursery. Including the General 
Regimen and Feeding of Infants and Children, and the Domestic Man- 
agement of the Ordinary Emergencies of Early Life, Massage, etc. 6th 
Edition. 25 Illustrations. $1.00 

TEMPERATURE AND CLINICAL CHARTS. See page 6. 

VOSWINKEL. Surgical Nursing. Second Edition, Enlarged. 

112 Illustrations. $1.00 

WESTLAND. The Wife and Mother. $1.50 



16 SUBJECT CATALOGUE. 

OBSTETRICS. 

CAZEAUX AND TARNIER. Midwifery. With Appendix by 
Mund6. The Theory and Practice of Obstetrics, including the Dis- 
eases ot Pregnancy and Parturition, Obstetrical Operations, etc. 
8th Edition. Illustrated by Chromo- Lithographs, Lithographs, and 
other full-page Plates, seven of which are beautifully colored, and 
numerous Wood Engravings. Cloth, $4.50 ; Full Leather, $5.50 

DAVIS. A Manual of Obstetrics. 3d Edition. Preparing. 

LANDIS. Compend of Obstetrics. 6th Edition, Revised by Wm. 
H. Wells, Assistant Demonstrator of Clinical Obstetrics, Jefferson 
Medical College. With 47 Illustrations, .80 ; Interleaved, $1.25. 

WINCKEL. Text-Book of Obstetrics, Including the Pathol- 
ogy and Therapeutics of the Puerperal State. Authorized 
Translation by J. Clifton Edgar, a.m., m.d. With nearly 200 Illus- 
trations. Cloth, $5.00 ; Leather, #6.00 

FULLERTON. Obstetric Nursing. 5th Ed. Illustrated. $1.00 



PATHOLOGY. 

BARLOW. General Pathology. 795 pages. 8vo. $5.00 

BLACK. Micro-Organisms. The Formation of Poisons. .75 

BLACKBURN. Autopsies. A Manual of Autopsies Designed for 
the Use of Hospitals for the Insane and other Public Institutions. 
Ten full-page Plates and other Illustrations. $1-25 

COPLIN. Manual of Pathology. Including Bacteriology, Technic 
of Post-Mortems, Methods of Pathologic Research, etc. 275 Illus- 
trations, many of which are original. 3d Edition. Nearly Ready. 
DA COSTA. Clinical Pathology of the Blood. Ilius. In Press. 
GILLIAM. Pathology. A Hand-Book for Students. 47 Illus. .75 

HALL. Compend of General Pathology and Morbid Anatomy. 

91 very fine Illustrations. 2d Edition. Preparing. 

HEWLETT. Manual of Bacteriology. 75 Illustrations. $3.00 

VIRCHOW. Post-Mortem Examinations. A Description and 
Explanation of the Method of Performing Them in the Dead House 
of the Berlin Charity Hospital, with Special Reference to Medico- 
Legal Practice. 3d Edition, with Additions. .75 

WHITACRE. Laboratory Text-Book of Pathology. With 
121 Illustrations. $ J -5° 

WILLIAMS. Bacteriology. A Manual for Students. 78 Illus- 
trations. $1.50 

PHARMACY. 

Special Catalogue of Books on Pharmacy sent free upon application. 

COBLENTZ. Manual of Pharmacy. A Complete Text-Book 
by the Professor in the New York College of Pharmacy, -zd Edition, 
Revised and Enlarged. 437 Illus. Cloth, $3.50; Sheep, $4.50 

BEASLEY. Book of 3100 Prescriptions. Collected from the 
Practice of the Most Eminent Physicians and Surgeons — English, 
French, and American. A Compendious History ot the Materia 
Medica, Lists of the Doses of all the Officinal and Established Pre- 
parations, an Index of Diseases and their Remedies. 7th Ed. $2.00 



MEDICAL BOOKS. 17 



BEASLEY. Druggists* General Receipt Book. Comprising 
a Copious Veterinary Formulary, Recipes in Patent and Proprietary 
Medicines, Druggists' Nostrums, etc. ; Perfumery and Cosmetics, 
Beverages, Dietetic Articles and Condiments, Trade Chemicals, 
Scientific Processes, and many Useful Tables, ioth Ed. $2.00 

BEASLEY. Pharmaceutical Formulary. A Synopsis of the 
British, French, German, and United States Pharmacopoeias. Com- 
prising Standard and Approved Formulae for the Preparations and 
Compounds Employed in Medicine. 12th Edition. $2.00 

PROCTOR. Practical Pharmacy. Lectures on Practical Phar- 
macy. With Wood Engravings and 32 Lithographic Fac-simile 
Prescriptions. 3d Edition, Revised, and with Elaborate Tables of 
Chemical Solubilities, etc. $3-oo 

ROBINSON. Latin Grammar of Pharmacy and Medicine. 
3d Edition. With elaborate Vocabularies. $!-75 

SAYRE. Organic Materia Medica and Pharmacognosy. An 
Introduction to the Study of the Vegetable Kingdom and the Vege- 
table and Animal Drugs. Comprising the Botanical and Physical 
Characteristics, Source, Constituents, and Pharmacopeial Prepar- 
ations, Insects Injurious to Drugs, and Parmacal Botany. With 
sections on Histology and Microtechnique, by W. C. Stevens. 
374 Illustrations. Second Edition. Cloth, $4.50 

SCOVILLE. The Art of Compounding. Second Edition, Re- 
vised and Enlarged. Cloth, $2.50 

STEWART. Compend of Pharmacy. Based upon " Reming- 
ton's Text-Book of Pharmacy." 5th Edition, Revised in Accord- 
ance with the U. S. Pharmacopoeia, 1890. Complete Tables of 
Metric and English Weights and Measures. .80 ; Interleaved. $1.25 

UNITED STATES PHARMACOPOEIA. 1890. 7 th Decennial 
Revision. Cloth, $2.50 (postpaid, $2.77); Sheep, $3.00 (postpaid, 
$3.27) ; Interleaved, $4.00 (postpaid, $4.50); Printed on one side oi 
page only, unbound, $3.50 (postpaid, $3.90). 

Select Tables from' the U. S. P. (1890). Being Nine of the Most 
Important and Useful Tables, Printed on Separate Sheets. Care- 
fully put up in patent envelope. .25 

POTTER. Hand-Book of Materia Medica, Pharmacy, and 
Therapeutics. 600 Prescriptions. 7th Ed. Clo.,$5.oo; Sh., £6.00 

PHYSICAL DIAGNOSIS. 

BROWN, Medical Diagnosis. A Manual of Clinical Methods. 
4th Edition. 1T2 Illustrations. Cloth, $2.25 

DA COSTA. Clinical Examination of the Blood. Illustrated. 

In Press. 

FENWICK. Medical Diagnosis. 8th Edition. Rewritten and 
very much Enlarged. 135 Illustrations. Cloth, $2.50 

MEMMINGER. Diagnosis by the Urine. 2d Ed. 24 Illus. $1.00 

TYSON. Hand-Book of Physical Diagnosis. For Students and 
Physicians. By the Professor of Clinical Medicine in the University 
of Pennsylvania. Illus. 3d Ed., Improved and Enlarged. With 
Colored and other Illustrations. $*-5° 

PHYSIOLOGY. 

BIRCH. Practical Physiology. An Elementary Class Book. 

62 Illustrations. $i-75 

BRUBAKER. Compend of Physiology. 9th Edition, Revised 

and Enlarged. Illustrated. .80; Interleaved, $1.25 

2 



18 SUBJECT CATALOGUE. 



London. 661 Illustrations, some of which are printed in colors. 

Cloth, $3.00; Leather, $3.75 

LANDOIS. A Text-Book of Human Physiology, Including 
Histology and Microscopical Anatomy, with Special Reference to 
the Requirements of Practical Medicine. 5th American, translated 
from the 9th German Edition, with Additions by Wm. Stirling, 
m.d.,d.sc. 845 Ulus., many of which are printed in colors. In Press. 

STARLING. Elements of Human Physiology. 100 Ills. $1.00 

STIRLING. Outlines of Practical Physiology. Including 
Chemical and Experimental Physiology, with Special Reference to 
Practical Medicine. 3d Edition. 289 Illustrations. #2.00 

TYSON. Cell Doctrine. Its History and Present State. $1.50 

PRACTICE. 

BEALE. On Slight Ailments; their Nature and Treatment. 

2d Edition, Enlarged and Illustrated. $1.25 

FOWLER. Dictionary of Practical Medicine. By various 
writers. An Encyclopaedia of Medicine. Clo.,$3.oo; Half Mor. $4.00 
GOULD AND PYLE. Cyclopedia of Practical Medicine and 
Surgery. A Concise Reference Handbook, Alphabetically 
Arranged, with particular Reference to Diagnosis and Treatment. 
Edited by Drs. Gould and Pyle, Assisted by 72 Special Con- 
tributors. Illustrated, one volume, Sheep or Half Morocco, $10 00; 
with Thumb Index, $11.00; Half Russia, Thumb Index, $12.00. 
JKtf* Complete descriptive circular with sample pages and illustra- 
tions of this book will be sent free upon application. 

HUGHES. Compend of the Practice of Medicine. 6th Edition, 
Revised and Enlarged. Just Ready. 

Part I. Continued, Eruptive, and Periodical Fevers, Diseases of the 
Stomach, Intestines, Peritoneum, Biliary Passages, Liver, Kid- 
neys, etc., and General Diseases, etc. 
Part II. Diseases of the Respiratory System, Circulatory System, 
and Nervous System; Diseases of the Blood, etc. 

Price of each part, .80; Interleaved, $1.25 
Physician's Edition. In one volume, including the above two 
parts, a Section on Skin Diseases, and an Index. 6th Revised 
Edition. 625 pp. Just Ready. Full Morocco, Gilt Edge, £2.25 
ROBERTS. The Theory and Practice of Medicine. The 
Sections on Treatment are especially exhaustive. 9th Edition, 
with Illustrations. Cloth. $4.50; Leather, $5.50 

TAYLOR. Practice of Medicine. 5th Edition. Cloth, $4.00 

TYSON. The Practice of Medicine. By James Tyson, m.d., 
Professor of Medicine in the University of Pennsylvania. A Com- 
plete Systematic Text-book with Special Reference to Diagnosis and 
Treatment. Illustrated. 8vo. 

Cloth, $5.50 ; Leather, $6.50 ; Half Russia, $7.50 

PRESCRIPTION BOOKS. 

BEASLEY. Book of 3100 Prescriptions. Collected from the 
Practice of the Most Eminent Physicians and Surgeons— English, 
French, and American. A Compendious History of the Materia, 
Medica, Lists of the Doses of all Officinal and Established Prepara- 
tions, and an Index of Diseases and their Remedies. 7th Ed. $2.00 



MEDICAL BOOKS. 19 



BEASLEY. Druggists' General Receipt Book. Comprising 
a Copious Veterinary Formulary, Recipes in Patent and Proprie- 
tary Medicines, Druggists' Nostrums, etc. ; Perfumery and Cos- 
metics, Beverages, Dietetic Articles and Condiments, Trade Chem- 
icals, Scientific Processes, and an Appendix of Useful Tables, 
ioth Edition, Revised. $2.00 

BEASLEY. Pocket Formulary. A Synopsis of the British, French, 
German, and United States Pharmacopoeias and the chief unofficial 
Formularies. 12th Edition. $2.00 



SKIN. 

BULKLEY. The Skin in Health and Disease. Illustrated. .40 
CROCKER. Diseases of the Skin. Their Description, Pathol- 
ogy, Diagnosis, and Treatment, with Special Reference to the Skin 
Eruptions of Children. 92 Illus. 3d Edition. Preparing. 

IMPEY. Leprosy. 37 Plates. 8vo. $3.50 

SCHAMBERG. Diseases of the Skin. 99 Illustrations. Being 
No. 16? Quiz-Compend? Series. Cloth, .80; Interleaved, $1.25 

VAN HARLINGEN. On Skin Diseases. A Practical Manual 
of Diagnosis and Treatment, with special reference to Differential 
Diagnosis. 3d Edition, Revised and Enlarged. With Formulae 
and 60 Illustrations, some of which are printed in colors. $2.75 



SURGERY AND SURGICAL DIS- 
EASES (see also Urinary Organs). 

BUTLIN. Operative Surgery of Malignant Disease. 2d Edi- 
tion. Illustrated. Octavo. Just Ready. $4- 50 
CRIPPS. Ovariotomy and Abdominal Surgery. Illus. $8.00 
DEAVER. Surgical Anatomy. A Treatise on Human Anatomy 
in its Application to Medicine and Surgery. With about 400 very 
Handsome full-page Illustrations Engraved from Original Drawings 
made by special Artists from Dissections prepared for the purpose. 
Three Volumes. Royal Square Octavo. 

Cloth, $21.00; Half Morocco or Sheep, $24.00 ; Half Russia, $27.00 
Complete descriptive circular and special ter?ns tipon application. 

DEAVER. Appendicitis, Its Symptoms, Diagnosis, Pathol- 
ogy, Treatment, and Complications. Elaborately Illustrated 
with Colored Plates and other Illustrations. 2d Edition. In Press. 

DULLES. What to Do First in Accidents and Poisoning. 
5th Edition. New Illustrations. $1.00 

FULLERTON. Surgical Nursing. 3d Edition. 69 Illus. $1 00 

HAMILTON. Lectures on Tumors, from a Clinical Stand- 
point. Third Edition, Revised, with New Illustrations. $1.25 

HEATH. Minor Surgery and Bandaging, nth Ed., Revised 
and Enlarged. 158 Illustrations, 62 Formulae, Diet List, etc. $1.25 

HEATH. Injuries and Diseases of the Jaws. 4th Edition. 
187 Illustrations. $4-5o 

HEATH. Lectures on Certain Diseases of the Jaws. 64 Illus- 
trations. Boards, .50 



20 SUBJECT CATALOGUE. 

HORWITZ. Compend of Surgery and Bandaging, including 
Minor Surgery, Amputations, Fractures, Dislocations, Surgical Dis- 
eases, and the Latest Antiseptic Rules, etc., with Differential Diagno- 
sis and Treatment. 5th Edition, very much Enlarged and Rear- 
ranged. 167 Illustrations, 98 Formulae. Clo.,.8o; Interleaved, $1.25 

JACOBSON. Operations of Surgery. Over 200 Illustrations. 

Cloth, $3.00 ; Leather, $4.00 
JACOBSON. Diseases of the Male Organs of Generation. 

88 Illustrations. $6.00 

LANE. Surgery of the Head and Neck, no Illustrations. 
2d Edition. $5.00 

MACREADY. A Treatise on Ruptures. 24 Full-page Litho- 
graphed Plates and Numerous Wood Engravings. Cloth, $6.00 
MAYLARD. Surgery of the Alimentary Canal. 97 Illustrations. 
2d Edition, Revised. Just Ready. #3-°o 

MOULLIN. Text-Book of Surgery. With Special Reference to 
Treatment. 3d American Edition. Revised and edited by John B. 
Hamilton, m.d., ll.d., Professor of the Principles of Surgery and 
Clinical Surgery, Rush Medical College, Chicago. 623 Illustrations, 
over 200 of which are original, and many of which are printed in 
colors. Handsome Cloth, $6.00; Leather, $7.00 

ROBERTS. Fractures of the Radius. A Clinical and Patho- 
logical Study. 33 Illustrations. $1.00 

SMITH. Abdominal Surgery. Being a Systematic Description ot 
all the Principal Operations. 224 Illus. 6th Ed. 2 Vols. Clo., $10.00 

SWAIN. Surgical Emergencies. Fifth Edition. Cloth, $1.75 

VOSWINKEL. Surgical Nursing. Second Edition, Revised and 
Enlarged, in Illustrations. $1.00 

WALSHAM. Manual of Practical Surgery. 6th Ed., Re- 
vised and Enlarged. With 410 Engravings. $3.00 

THROAT AND NOSE (see also Ear). 
COHEN. The Throat and Voice. Illustrated. .40 

HALL. Diseases of the Nose and Throat. Two Colored 

Plates and 59 Illustrations. New Edition Preparing. 

HOLLOPETER. Hay Fever. Its Successful Treatment. £1.00 

KNIGHT. Diseases of the Throat. A Manual for Students. 

Illustrated. Nearly Ready. 

MACKENZIE. Pharmacopoeia of the London Hospital for 

Dis. of the Throat. 5th Ed., Revised by Dr. F. G. Harvey. $1.00 
McBRIDE. Diseases of the Throat, Nose, and Ear. A Clinical 

Manual. With colored Illus. from original drawings. 2d Ed. $6.00 

POTTER. Speech and its Defects. Considered Physiologically, 
Pathologically, and Remedially. $1.00 

URINE AND URINARY ORGANS. 

ACTON. The Functions and Disorders of the Reproductive 
Organs in Childhood, Youth, Adult Age, and Advanced Life, 
Considered in their Physiological, Social, and Moral Relations. 
8th Edition. $i-75 



MEDICAL BOOKS. 21 



BEALE. One Hundred Urinary Deposits. On eight sheets, 
for the Hospital, Laboratory, or Surgery. Paper, #2.00 

HOLLAND. The Urine, the Gastric Contents, the Common 
Poisons, and the Milk. Memoranda, Chemical and Microscopi- 
cal, for Laboratory Use. Illustrated and Interleaved. 6th Ed. $1.00 

JACOBSON. Diseases of the Male Organs of Generation. 88 

Illustrations. $6.00 

KLEEN. Diabetes and Glycosuria. $2.50 

MEMMINGER. Diagnosis by the Urine. 2d Ed. 24 Iilus. $1.00 

MORRIS. Renal Surgery, with Special Reference to Stone in the 
Kidney and Ureter and to the Surgical Treatment of Calculous 
Anuria. Illustrated. $2.00. 

MOULLIN. Enlargement of the Prostate. Its Treatment and 
Radical Cure. 2d Edition. Illustrated. Jtist Ready. $*-75 

MOULLIN. Inflammation of the Bladder and Urinary Fever. 
Octavo. $i-5o 

SCOTT. The Urine. Its Clinical and Microscopical Examination. 
41 Lithographic Plates and other Illustrations. Nearly Ready. 

TYSON. Guide to Examination of the Urine. For the Use of 
Physicians and Students. With Colored Plate and Numerous Illus- 
trations engraved on wood. 9th Edition, Revised. $1-25 

VAN NUYS. Chemical Analysis of Healthy and Diseased 
Urine, Qualitative and Quantitative. 39 Illustrations. $1.00 

VENEREAL DISEASES. 

COOPER. Syphilis. 2d Edition, Enlarged and Illustrated with 

20 full-page Plates. $5.00 

GOWERS. Syphilis and the Nervous System. 1.00 

VETERINARY. 

BALLOU. Veterinary Anatomy and Physiology. 29 Graphic 
Illustrations. .80; Interleaved, #1.25 

TUSON. Veterinary Pharmacopoeia. Including the Outlines of 
Materia Medica and Therapeutics. 5th Edition. $2.25 

WOMEN, DISEASES OF. 

BYFORD (H. T.). Manual of Gynecology. Second Edition, 
Revised and Enlarged by 100 pages. With 341 Illustrations, many 
of which are from original drawings. $3-oo 

DUHRSSEN. A Manual of Gynecological Practice. 105 
Illustrations. $ 1 -S° 

FULLERTON. Surgical Nursing. 3d Edition, Revised and 
Enlarged. 69 Illustrations. $1.00 

LEWERS. Diseases of Women. 146 Illus. 5th Ed. $2.50 

MONTGOMERY. Gynecology. A Text-Book. Abe ut 5c o Illus- 
trations. 8vo. In Press. 

WELLS. Compend of Gynecology. Illustrated. 2d Edition. 

.80; Interleaved, $1. 25 



22 SUBJECT CATALOGUE. 

COMPENDS. 



From The Southern Clinic. 

" We know of no series of books issued by any house that so fully 
meets our approval as these ?Quiz-Compends?. They are well ar- 
ranged, full, and concise, and are really the best line of text-books that 
could be found for either student or practitioner." 



BLAKISTON'S PQUIZ-COMPENDS? 

The Best Series of Manuals for the Use of Students. 
Price of each, Cloth, .80. Interleaved, for taking Notes, $1.25. 

4&~ These Compends are based on the most popular text-books 
and the lectures of prominent professors, and are kept constantly re- 
vised, so that they may thoroughly represent the present state of the 
subjects upon which they treat. 

j&tf" The authors have had large experience as Quiz-Masters and 
attaches of colleges, and are well acquainted with the wants of students. 

MS" They are arranged in the most approved ,'form, thorough and 
concise, containing over 6oo fine illustrations, inserted wherever they 
could be used to advantage. 

4S* Can be used by students of way college. 

&$- They contain information nowhere else collected in such a 
condensed, practical shape. Illustrated Circular free. 

No. i. POTTER. HUMAN ANATOMY. Sixth Revised and 
Enlarged Edition. Including Visceral Anatomy. Can be used 
with either Morris's or Gray's Anatomy. 117 Illustrations and 16 
Lithographic Plates of Nerves and Arteries, with Explanatory 
Tables, etc. By Samuel O. L. Potter, m.d., Professor of the 
Practice of Medicine, Cooper Medical College, San Francisco ; late 
A. A. Surgeon, U. S. Army. 

No. 2. HUGHES. PRACTICE OF MEDICINE. Part I. Sixth 
Edition, Enlarged and Improved. By Daniel E. Hughes, m.d., 
Physician-in-Chief, Philadelphia Hospital, late Demonstrator ot 
Clinical Medicine, Jefferson Medical College, Phiia. 

No. 3. HUGHES. PRACTICE OF MEDICINE. Part II. 
Sixth Edition, Revised and Improved. Same author as No. 2. 

No. 4. BRUBAKER. PHYSIOLOGY. Ninth Edition, with 
new Illustrations and a table of Physiological Constants. Enlarged 
and Revised. By A. P. Brubaker, m.d., Professor of Physiology 
and General Pathology in the Pennsylvania College of Dental 
Surgery ; Adjunct Professor of Physiology, Jefferson Medical 
College, Philadelphia, etc. 

No. 5. LANDIS. OBSTETRICS. Sixth Edition. By Henry G. 
Landis, m.d. Revised and Edited by Wm. H. Wells, m.d., 
Instructor of Obstetrics, Jefferson Medical College, Philadelphia. 
Enlarged. 47 Illustrations. 

No. 6. POTTER. MATERIA MEDICA, THERAPEUTICS, 
AND PRESCRIPTION WRITING. Sixth Revised Edition 
(U. S. P. 1890). By Samuel O. L. Potter, m.d., Professor of 
Practice, Cooper Medical College, San Francisco ; late A. A. Sur- 
geon, U. S. Army. 



MEDICAL BOOKS. 23 



PQUIZ-COMPENDS ?— Continued. 

No. 7. WELLS. GYNECOLOGY. Second Edition. ByWM.H. 
Wells, m.d., Instructor of Obstetrics, JeffersoD College, Philadel- 
phia. 140 Illustrations. 

No. 8. GOULD AND PYLE. DISEASES OF THE EYE 
AND REFRACTION. Second Edition. Including Treatment 
and Surgery, and a Section on Local Therapeutics. By George 
M. Gould, m.d., and W. L. Pyle, m.d. With Formula, Glossary, 
Tables, and 109 Illustrations, several of which are Colored. 

No. 9. HORWITZ. SURGERY, Minor Surgery, and Bandag- 
ing. Fifth Edition, Enlarged and Improved. By Orville 
Horwitz, b. s., m.d., Clinical Professor of Genito-Urinary Surgery 
and Venereal Diseases in Jefferson Medical College ; Surgeon to 
Philadelphia Hospital, etc. With 98 Formulae and 71 Illustrations. 

No. 10. LEFFMANN. MEDICAL CHEMISTRY. Fourth 

Edition. Including Urinalysis, Animal Chemistry, Chemistry of 
Milk, Blood, Tissues, the Secretions, etc. By Henry Leffmann, 
m.d., Professor of Chemistry in Pennsylvania College of Dental 
Surgery and in the Woman's Medical College, Philadelphia. 

No. 11. STEWART. PHARMACY. Fifth Edition. Based upon 
Prof. Remington's Text-Book of Pharmacy. By F. E. Stewart, 
m.d., ph.g., late Quiz-Master in Pharmacy and Chemistry, Phila- 
delphia College of Pharmacy ; Lecturer at Jefferson Medical 
College. Carefully revised in accordance with the new U. S. P. 

No. 12. BALLOU. VETERINARY ANATOMY AND PHY- 
SIOLOGY. Illustrated. By Wm, R. .Ballou, m.d., Professor 
of Equine Anatomy at New York College of Veterinary Surgeons ; 
Physician to Bellevue Dispensary, etc. 29 graphic Illustrations. 

No. 13. WARREN. DENTAL PATHOLOGY AND DEN- 
TAL MEDICINE. Third Edition, Illustrated. Containing 
a Section on Emergencies. By Geo. W. Warren, d.d.s., Chiet 
ot Clinical Staff, Pennsylvania College of Dental Surgery. 

No. 14. HATFIELD. DISEASES OF CHILDREN. Second 
Edition. Colored Plate. By Marcus P. Hatfield, Profes- 
sor of Diseases of Children, Chicago Medical College. 

No. 15. HALL. GENERAL PATHOLOGY AND MORBID 
ANATOMY. 91 Illustrations. By H. Newberry Hall, ph.g., 
m.d., late Professor of Pathology, Chicago Post-Graduate Medi- 
cal School. Second Edition. Preparing. 

No. 16. DISEASES OF THE SKIN. By Jay T. Schamberg, 
m.d., Professor of Diseases of the Skin, Philadelphia Polyclinic. 
With 99 handsome Illustrations. 

Price, each, Cloth, .80. Interleaved, for taking Notes, $1.25. 

In preparing, revising, and improving Blakiston's ? Quiz-Com- 
pends ? the particular wants of the student have always been kept in 
mind. 

Careful attention has been given to the construction of each sentence, 
and while the books will be found to contain an immense amount of 
knowledge in small space, they will likewise be found easy reading ; 
there is no stilted repetition of words ; the style is clear, lucid, and dis- 
tinct. The arrangement of subjects is systematic and thorough ; there 
Is a reason for every word. They contain over 600 illustrations. 



Morris' 
Anatomy 

Second Edition, 
Revised and Enlarged. 

790 Illustrations, of which many 
are in Colors. 



Royal Octavo. Cloth, $6.00 ; Sheep, $7.00 ; 
Half Russia, $8.00. 



from The Medical Record, New York. 

" The reproach that the English language can boast of no 
treatise on anatomy deserving to be ranked with the masterly 
works of Henle, Luschka, Hyrtl, and others, is fast losing 
its force. During the past few years several works of great 
merit have appeared, and among these Morris's " Anatomy " 
seems destined to take first place in disputing the palm in 
pnatomical fields with the German classics. The nomencla- 
ture, arrangement, and entire general character resemble 
strongly those of the above-mentioned handbooks, while in 
the beauty and profuseness of its illustrations it surpasses 
them. . . . The ever-growing popularity of the book 
with teachers and students is an index of its value, and it 
may safely be recommended to all interested. ,, 



*** Handsome Descriptive Circular, with 
Sample Pages and Colored Illustrations, 
will be sent free upon' application. 



1900 






